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DURAN Borosilicate Glass 3.3: Properties & Laboratory Uses

SOSCLEANROOM  |  TECHNICAL VAULT  |  DWK LIFE SCIENCES EDUCATION SERIES  |  ARTICLE 05

DURAN Borosilicate Glass 3.3: Properties, Chemical Resistance & Laboratory Applications.

A manufacturer-grounded technical guide to low-expansion Type I laboratory glass, hydrolytic and chemical resistance, thermal shock, sterilization, pressure safety, GL 25 / GL 45 / GLS 80 closure systems and DURAN laboratory products.

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Article 05 | Essential principle

Borosilicate 3.3 is an engineered glass—not a universal guarantee of chemical or process compatibility.

DURAN® is DWK Life Sciences’ premium laboratory glassware brand associated with borosilicate glass 3.3. Its combination of low thermal expansion, high hydrolytic resistance, broad chemical durability and optical clarity makes it useful for laboratory bottles, beakers, flasks and specialized glass systems. Those properties are meaningful, but the geometry, attached components, processing conditions and required documentation still determine whether a particular product is fit for an application.

This fifth article in the DWK Life Sciences Technical Education Series explains what the designation 3.3 means, why glass sometimes corrodes despite its reputation for inertness, how to evaluate thermal shock and pressure, and when specialized DURAN bottle systems are appropriate. It connects those principles to published SOScleanroom products, while recognizing that the assortment is still expanding.

The operating rule

Select the glass type + individual product geometry + closure/contact components + temperature and chemical exposure + required evidence together. Type I borosilicate classification is important material information, not an automatic sterility claim or validation of a finished product process.

Material science explained

What “3.3” describes—and the properties DWK actually publishes.

The “3.3” designation refers to the approximate mean linear thermal-expansion coefficient of borosilicate glass over the specified 20–300 °C interval. It is a material characteristic, not a 3.3 mm wall thickness or a thermal-shock rating for every vessel. DWK reports the following values for 3.3 expansion borosilicate glass in its technical glass-properties reference.

DWK-reported property Borosilicate glass 3.3 Why it matters
Thermal expansion (20–300 °C) 3.3 × 10−6 K−1 Relatively small dimensional changes when temperature changes; generally better thermal-shock tolerance than higher-expansion glass under comparable conditions.
Density at 25 °C 2.23 g/cm³ Useful for understanding material mass; not a substitute for the weight of a finished bottle.
Softening point 821 °C A material-characterization value; not a safe recommended service temperature for assembled labware.
Annealing point 565 °C Relevant to glass stress relief and manufacturing, not a routine sterilization instruction.
Hydrolytic resistance HGB 1 under ISO 719 Indicates high resistance to attack by water under the defined test method.
Acid resistance S1 under DIN 12116 High acid resistance in the relevant standard test; significant chemical exceptions remain.
Alkali resistance A2 under ISO 695 Glass is not impervious to alkaline attack, particularly under aggressive conditions.

Primary technical source: DWK Glass Types & Properties. Values describe the glass material; an individual product’s allowable service temperature, loading and closure limits must be obtained separately.

Material class versus final product

Borosilicate 3.3, other borosilicates and soda-lime glass do not share identical performance.

Glass family DWK-reported thermal expansion Practical selection implication
3.3 expansion borosilicate 3.3 × 10−6 K−1 Low-expansion glass used for DURAN products; high chemical durability and strong suitability for many controlled thermal processes.
4.9 expansion borosilicate 4.9 × 10−6 K−1 Different thermal and dimensional behavior; do not infer that all borosilicates are identical.
5.4 expansion amber borosilicate 5.4 × 10−6 K−1 A distinct composition and thermal behavior; not automatically equivalent to amber DURAN 3.3.
7.8 / 9.1 expansion soda-lime 7.8 / 9.1 × 10−6 K−1 Typically higher expansion and different chemical/hydrolytic resistance than 3.3 borosilicate.

DWK identifies DURAN borosilicate 3.3 as conforming to Type I neutral glass classifications used by major pharmacopoeias. Those glass-material designations do not establish that any unprocessed laboratory bottle is an approved finished-drug container, supplied sterile, or ready for use in aseptic production. DWK DURAN brand overview.

Chemical resistance and its limits

Where DURAN performs strongly—and where chemistry can still damage the surface.

DWK characterizes 3.3 borosilicate as highly resistant to water, many acids, salts, halogens and organic solvents. Its high silica content and low alkali-metal-oxide content help explain its hydrolytic behavior. But no laboratory glass should be treated as universally inert: aggressive chemicals, elevated temperature, extended contact and surface damage can change performance.

Exposure General manufacturer-supported behavior Required qualification
Water, aqueous salts and many common acids Generally very strong resistance to attack for borosilicate 3.3. Identify analytes, time, concentration, temperature, target ions and method detection limits.
Many organic solvents Glass walls are often a suitable candidate for solvent handling. The cap/liner and any tubing may be the limiting materials; assess solvent volatility and evaporation.
Hydrofluoric acid (HF) Explicit exception: HF can chemically attack and dissolve silica-containing glass. Use appropriate specially selected compatible containment and laboratory chemical safety controls; do not select ordinary DURAN glass for HF.
Hot concentrated phosphoric acid DWK identifies appreciable chemical attack under this aggressive condition. Verify actual concentration, processing temperature and contact duration.
Strong alkaline solutions, especially when hot Can corrode glass; borosilicate 3.3 meets an alkali-resistance class, not an “alkali-proof” claim. Evaluate pH, cleaning chemistry, temperature, frequency and surface condition.

Analytical integrity extends beyond visible corrosion

A vessel can look intact while low-level ion leaching, analyte adsorption, cap-derived extractables or environmental contamination still matter for a sensitive method. Qualify the whole sample-contact system using application-relevant blanks, recovery and suitability testing.

Manufacturer source: DWK Glass Types & Properties.

Heat, thermal shock and repeated cycles

Low expansion helps—but does not eliminate thermal stress.

Borosilicate 3.3 generally tolerates temperature changes better than higher-expansion glass of comparable form, but wall thickness, vessel geometry, scratches, support contact, temperature gradients and attached components determine the practical limit. A glass product can fail when one side heats much faster than another, even when the bulk material has a high softening point.

Heating and cooling

Control temperature gradients

Avoid sudden placement of hot glass on cold or wet benches; use suitable supports and the manufacturer’s process instructions.

Steam processing

Review the complete assembly

An autoclavable glass body does not mean every fitted cap, liner, tubing assembly or process setup is suitable. Control closure configuration and pressure equalization under approved procedures.

Dry-heat exposure

Do not use softening point as a limit

Verify actual product service temperatures, coatings, graduations, sealing components and process conditions.

Repeated use

Inspect condition

Reject chipped, cracked, deeply scratched or otherwise compromised items. Heating and use cycles do not excuse mechanical damage.

Specially coated bottles

Coating changes the rules

Protect or safety coatings may have substantially lower temperature limits than the underlying borosilicate glass.

Unverified pressure conditions

Never generalize

Thermal resistance does not establish suitability for vacuum, positive pressure, sealed heating or pressure-assisted processes.

An important DWK product-specific example

DWK reports 160 K thermal-shock resistance for its DURAN Premium GL 45 bottle, with specialized PFA cap and pouring components. That is a claim for a specified product configuration, not a 160 K rating for every DURAN bottle, cap or coated item. View the premium bottle manufacturer description.

Pressure, vacuum and glass safety

An ordinary reagent bottle is not a pressure vessel.

DWK explicitly warns that conventional laboratory bottles should not be used under substantial pressure or vacuum unless they are designed and identified for that use. Pressure and temperature stresses can combine, increasing breakage risk. The low thermal expansion of DURAN glass alone does not change those requirements.

Scenario Do Do not
Vacuum-driven work Select a manufacturer-rated pressure/vacuum product and verify its allowable conditions. Assume a standard GL 45 media bottle becomes vacuum-rated because it has borosilicate walls.
Positive pressure or gas generation Use approved purpose-built systems, proper pressure controls and safety shielding. Seal a standard laboratory bottle and heat or pressurize it.
Liquid transfers Evaluate the actual bottle, connectors, tubing and intended system pressure. Treat an HPLC-style bottle with multiple necks as pressure-certified without manufacturer proof.
Used or damaged glass Inspect for cracks, chips, abrasions and compromised surfaces. Operate suspect glassware under stress or try to repair pressure-bearing vessels casually.

DWK separately offers purpose-built DURAN pressure plus+ products with modified geometry; the specific published range differs from standard DURAN bottle designs. DWK laboratory pressure safety guidance.

Product families and design features

DURAN ORIGINAL, YOUTILITY, PURE and specialized systems answer different needs.

General laboratory

DURAN ORIGINAL

Multipurpose borosilicate bottles with standardized closure options. Verify clear or amber, capacity, GL thread, cap/pour ring and autoclavability on the specific SKU.

Ergonomic handling

DURAN YOUTILITY

A bottle system with handling-oriented design and dedicated accessories. Do not assume every cap or accessory matches ORIGINAL or PURE bottles.

Pharmaceutical intermediates

DURAN PURE

A documented family with ambered Type I 3.3 glass, protective covers, batch documentation, traceability and specific caps; bottles are not automatically supplied sterile or pre-washed.

Solvent workflows

DURAN HPLC / Hydra

Specially designed bottle systems and multiple connection points for HPLC mobile-phase handling; match GL 45 connections and solvent-contact materials.

Volumetric preparation

DURAN volumetricware

Graduated and calibrated product families follow relevant item standards; a general graduated reagent bottle is not a Class A volumetric flask.

Pressure applications

DURAN pressure plus+

Specific pressure-rated geometry and documented operating conditions; do not generalize its limits to ordinary bottles.

DWK references: DURAN Bottle System; DURAN brand portfolio; DURAN PURE technical overview.

The bottle/closure interface

GL 25, GL 45 and GLS 80 are not interchangeable opening systems.

An important buyer distinction is that DURAN uses several different closure platforms. The thread designation must be matched exactly. A cap seal, liner or pouring ring is part of the system that determines whether the assembly meets chemical and handling needs.

Finish Live or manufacturer-verified example Selection checkpoint
GL 25 DURAN PURE 818061406, amber, 25 mL; matching PURE GL 25 cap 891081306 listed separately. Confirm the exact GL 25 cap and its liner or contact materials. Do not use a GL 45 cap.
GL 45 DURAN PURE 818063604, amber, 250 mL; Hydra 218505453 uses multiple GL 45 necks. Check each individual cap/tubing connection, seal and analytical-contact requirements.
GLS 80 DURAN PURE 818666307, amber 2000 mL wide-mouth bottle; matching GLS 80 cap 891169109 listed separately. Confirm the wide-mouth GLS 80 closure, PTFE-coated silicone seal and any required pouring components.

Practical procurement rule

A protective transport cover is not a substitute for a selected process closure. The manufacturer’s DURAN PURE wide-mouth bottle listing specifies no screw cap or pouring ring included for 818666307. Order a suitable matched cap and accessories separately as required.

Type I glass and pharmaceutical supply chains

Why DURAN PURE’s documentation matters without overstating qualification.

DWK describes DURAN PURE as an amber borosilicate Type I bottle family for pharmaceutical intermediate handling. Manufacturer-provided attributes include protective covers, defined lot delivery, batch hydrolytic testing, Certificate of Analysis (CoA) availability, traceability and formal change-control arrangements. These are meaningful input documents for a regulated supplier-qualification process.

A Type I classification describes glass properties under applicable pharmacopeial tests. It does not establish microbial sterility, endotoxin status, acceptable container-closure integrity or compatibility with a particular drug formula. The manufacturer states that DURAN PURE bottles are not additionally washed after manufacturing; packaging and controlled handling must not be interpreted as a pre-cleaned, ready-to-fill sterile state.

DWK references an FDA Type III Packaging Material Drug Master File for this product family. A DMF filing is not an FDA approval of a bottle, process or customer drug product. The customer remains responsible for applicable qualification and validated cleaning/sterilization steps.

Cleanroom distinction verified with DWK

For the DURAN PURE system, DWK states that its caps are produced and packaged in an ISO Class 7 cleanroom environment, while the glass bottles are not formed in a cleanroom. Controlled handling and protective covers reduce exposure but are not sterility certification. Manufacturer DURAN PURE FAQs.

HPLC mobile phases and sample integrity

Why low-extractables glass, closure components and headspace deserve separate attention.

DURAN borosilicate 3.3 is a useful candidate for HPLC solvent reservoirs because of broad solvent resistance and comparatively low inorganic ion extractables from the glass. But instrument suitability also depends on the mobile phase, tubing, degassing configuration, connection seals and intended ventilation or pressure management. A bottle may be chemically suitable yet still compromise an analytical method through an incompatible closure or poorly controlled transfer.

A concrete live example is DURAN GL 45 Hydra 218505453: DWK specifies a 1,000 mL square bottle with four GL 45 side necks and a central GL 45 opening, designed to accommodate multiple HPLC connections. Its manufacturer description calls out space-saving geometry, five GL 45 connection points and traceability. It is not represented here as a pressure-certified reservoir.

  • Mobile-phase chemistry: identify solvent blend, pH, additives, oxygen sensitivity and exposure duration.
  • Wetted materials: document glass, cap seals, PTFE/silicone or other liners, tubing and connectors.
  • Contamination control: use appropriate analytical blanks and extraction/adsorption checks for the target method.
  • Handling: use approved spill containment, capping, ventilation and solvent-safety controls.
  • Maintenance: establish cleaning/rinsing and change schedules for the actual system.

Manufacturer source: DWK 218505453 Hydra technical details.

Applications and product qualification

A selection matrix for common DURAN glassware decisions.

Application Product-family starting point Mandatory technical evidence
Routine compatible reagent storage DURAN ORIGINAL or matching borosilicate bottle Chemical compatibility; GL closure; temperature, cleaning and storage instructions.
Light-sensitive intermediate storage DURAN PURE amber bottle candidate Amber/light-protection specification; cap compatibility; batch evidence; sampling and transfer procedures.
HPLC solvent reservoir DURAN Hydra or applicable HPLC reservoir GL connection arrangement, solvent/liner resistance, validated system configuration and solvent controls.
Media preparation and steam sterilization Product-specific autoclavable DURAN bottle Validated cycle; cap instructions; material transfer; correct liquid/headspace and post-cycle checks.
Repeated heating and chemical work Suitable DURAN flasks or beakers Product design; thermal loading method; surface condition; risk assessment.
Pressure/vacuum operation Only the rated DURAN pressure plus+ family where appropriate Exact permissible pressure/vacuum, temperature, accessory configuration and safety procedure.
Regulated pharmaceutical processing DURAN PURE or another qualified specific glass system Glass classification, CoA, change control, cleanliness, sterility process and site qualification.

Do not use nominal capacity or “borosilicate” alone as approval. Where a controlled process is involved, retain current manufacturer documents and the site-approved decision record.

Verified current SOScleanroom listings

Connect material science with available DURAN product pages.

The following entries were confirmed from current SOScleanroom category listings and checked against the manufacturer descriptions where applicable. These are examples, not proof of stock on hand or a complete DWK assortment. Check the current listing, case configuration and documentation before ordering.

Catalog quality checkpoint

DWK manufacturer item 818665405 is a 1,000 mL GLS 80 amber wide-mouth DURAN PURE bottle. At the time of review, the SOScleanroom category listing for that same number displayed an inconsistent 250 mL GL 45 title. This guide intentionally excludes that conflicting listing from the featured cards pending a catalog correction; consult DWK 818665405 manufacturer specifications.

Browse the DWK bottle category and caps and closures category for the current assortment.

Cleaning, sterilization and handling

A product can be autoclavable without arriving sterile or already clean.

A manufacturer “autoclavable” attribute means the referenced product is designed to tolerate specified autoclave conditions; it does not mean the delivered item is sterile. DWK’s DURAN PURE documentation confirms that bottles are not washed after manufacturing. Controlled pharmaceutical operations should validate or qualify the necessary cleaning and sterilization processes for the actual assembly and its intended use.

  • Incoming inspection: identify the exact SKU, closure status, packaging integrity, chips, cracks and lot or Retrace Code.
  • Cleaning method: choose compatible chemistry, appropriate rinsing water and validated residue controls based on the analytical or GMP context.
  • Autoclave preparation: follow approved closure/venting instructions; never create an unapproved sealed pressure vessel during heating.
  • Post-processing: manage cooling, moisture, sterility protection, drying and clean-hold conditions.
  • Reuse: track scratches, etching, mineral deposits and damaged rims; separate damaged glass from usable inventory.
  • Waste: apply site procedures for chemical contamination and specialty laboratory glass; do not assume borosilicate is accepted with ordinary container glass recycling.

For DURAN PURE, DWK discusses common steam sterilization cycles around 121 °C for 15–20 minutes for compatible configurations, while warning that temperature tolerance can differ for cap types and liner constructions. The site’s validated cycle and the exact product documentation govern use. DURAN PURE manufacturer FAQ.

Procurement and technical specification

Ten details to capture before comparing catalog numbers or approving substitutions.

01 | Identification

Manufacturer and exact SKU

DWK product number, product family, revision, pack quantity and current online status.

02 | Glass formulation

Borosilicate 3.3 evidence

Confirm Type I status or relevant ISO/ASTM/material standard for the specific item.

03 | Geometry

Shape and useful volume

Nominal capacity, bottle height/diameter, opening, working volume and instrument clearance.

04 | Closure

Correct neck and seal

GL 25, GL 45 or GLS 80; cap type, liner, pour ring and whether included.

05 | Chemistry

Sample and process media

Chemical species, concentration, pH, contact duration, cleanliness and analyte limits.

06 | Processing

Thermal and mechanical limits

Steam cycle, dry heat, temperature ramps, handling, pressure or vacuum restrictions.

07 | Protection

Light and breakage concerns

Clear/amber selection, coatings, secondary containment and relevant light-protection evidence.

08 | Documentation

Quality records

CoA/CoC, manufacturer lot, Retrace Code, change notices and supplier qualification status.

09 | Cleanliness

Controlled-environment entry

Packaging, cleaning, sterilization, transfer and contamination-control documentation.

10 | Change control

Approved alternatives

Define the tests needed to qualify a different bottle, cap, liner or manufacturer lot.

The right question is not “Is it Type I?”

Ask whether the actual container and complete closure assembly are appropriate for your medium, equipment, processing, contamination limits and documentation requirements. A different glass shape, neck finish or cap can be a material process change.

Failure modes and investigations

Practical diagnosis for laboratory glassware problems.

Observed issue What to investigate Controlled action
Glass cracking after heating Rapid temperature gradient; cold contact surface; pre-existing chip/scratch; wrong vessel geometry. Quarantine, inspect process and glass condition; review manufacturer instructions before reuse.
Cloudy, etched or dull glass Aggressive alkali cleaning; incompatible chemistry; repeated hot exposure; deposits. Distinguish residue from permanent etching and validate cleaning changes.
Unexpected HPLC blank peaks / ions Glass wash/rinse background; cap liner; tubing; sample-contact contaminants. Use method-specific blanks and component-by-component qualification.
Solvent loss or odor Unmatched cap/liner; improper seal; volatile solvent and transfer setup. Confirm closure, ventilation and approved storage method.
Bottle leak after autoclaving Incorrect cap setting; damaged neck; liner mismatch; thermal deformation. Review entire assembly and cycle; do not rely on glass material alone.
Wrong cap received GL 25 / GL 45 / GLS 80 confusion; ordering description incomplete. Use exact manufacturer part number and verify matching closure geometry.
Supplier SKU description conflict Website title disagrees with manufacturer capacity or finish. Hold product-page publication or purchasing decision pending manufacturer verification and correction.

DURAN borosilicate 3.3 FAQ

Answers to common laboratory material, handling and purchasing questions.

What does the 3.3 in DURAN borosilicate glass 3.3 mean?

It refers to the approximate linear thermal-expansion coefficient of 3.3 × 10⁻⁶ K⁻¹ over the stated 20–300 °C range, not to thickness or a vessel-specific temperature limit.

Is DURAN borosilicate glass chemically inert to everything?

No. DWK identifies hydrofluoric acid, hot concentrated phosphoric acid and strong alkaline conditions as important attack mechanisms. All sensitive analytical applications need whole-system qualification.

Is DURAN 3.3 equivalent to ordinary soda-lime glass?

No. DWK publishes different thermal-expansion and hydrolytic properties. Select the documented material required by the application.

Does Type I glass mean a bottle is sterile?

No. Type I is a glass/hydrolytic classification; supplied sterility, cleaning, endotoxin status and process suitability are separate attributes.

Can all DURAN bottles be autoclaved?

No blanket rule applies to the entire portfolio. Confirm the exact bottle, cap, pouring ring, liner and any coating with the current manufacturer instructions.

Does the DURAN PURE protective cover make the bottle sterile?

No. DWK explains that DURAN PURE bottles are not additionally washed after manufacturing; a protective cover reduces exposure but does not certify sterility.

Can any GL 45 cap fit a GL 25 or GLS 80 bottle?

No. Those are different finish systems. Select the exact matched closure and confirm the specific seal or liner.

Are standard DURAN reagent bottles safe for vacuum or pressure?

No. DWK advises that only specifically designated pressure/vacuum products, such as appropriate DURAN pressure plus+ items, be used under defined pressure conditions.

Are bottle graduations a substitute for volumetric calibration?

Not automatically. General reagent bottle graduations are commonly for approximate filling; quantitative measurement needs a vessel meeting the required volumetric tolerances.

Does amber DURAN glass guarantee protection for every light-sensitive substance?

No. Amber specifications can support defined light-protection needs, but the target compound’s wavelength sensitivity, exposure and the exact bottle’s spectral performance must be evaluated.

Does a manufacturer Drug Master File mean a DURAN bottle is FDA approved?

No. The manufacturer notes a Type III packaging material DMF filing for some DURAN PURE items; that filing does not constitute FDA approval of a bottle or drug product.

Why might a lab select the DURAN Hydra 218505453?

It provides a 1 L square borosilicate solvent bottle with four side GL 45 necks and a main GL 45 opening, enabling a specialized multi-connection HPLC configuration when appropriately assembled.

How does SOScleanroom handle newly added DURAN products?

The DWK assortment is expanding. Use live catalog listings for currently published items and verify manufacturer specifications for any new SKU before purchasing or approving use.

Continue the DWK education series

Progressive technical depth with verified links—not assumed publication dates.

Article 02 | Previous

Laboratory Glass vs. Plastic

Material selection and chemical compatibility. Add published link after live URL verification.

Article 03 | Previous

WHEATON Laboratory Bottles

Neck finishes, bottle materials and specialty container design. Add link after publication verification.

Article 04 | Previous

WHEATON Laboratory Vials & Closures

Caps, septa, inserts and analytical sample integrity. Add link once verified live.

Article 05 | Current

DURAN Borosilicate Glass 3.3

Thermal and chemical properties, laboratory applications and regulated selection.

Article 06 | Planned

KIMBLE Laboratory Glassware

Understand KIMAX glass types, calibrated volumetrics, tubes and practical selection.

Explore the full SOScleanroom Technical Vault or the current DWK collection. This article intentionally does not link to unverified URLs for Articles 02–04.

Primary technical sources

Manufacturer documentation underpinning the material, product and safety claims.

The manufacturer references below are provided for source traceability. Interpret material reference tables together with current documentation for the specific product and the laboratory’s validated methods.

Scope statement: This article is educational and is not an operating procedure, sterility certification, regulatory approval, container-closure integrity study or chemical-compatibility guarantee. Confirm the manufacturer’s current documents and site-approved quality requirements before use.

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SOScleanroom technical education • DURAN and DWK Life Sciences are trademarks of their respective owners. Manufacturer-source review: November 2026. Confirm current specifications, status and availability for each exact SKU.