Corning® PYREX® 7740 Borosilicate Glass

Corning® PYREX® 7740 borosilicate glass is a reliable material for precision glass components that require low thermal expansion, good optical transparency and strong chemical durability. With a thermal expansion coefficient of 3.3 × 10⁻⁶ /°C, a softening point of about 820°C and excellent resistance to water, acid and many chemical environments, PYREX® 7740 is widely used in laboratory glassware, optical windows, filter substrates, medical devices, lighting components, sight windows and industrial process parts.

We supply customized PYREX® 7740 borosilicate glass components according to drawings, dimensions, thickness requirements and application conditions. Available processing can include cutting, grinding, polishing, drilling and other precision fabrication for laboratory, optical, medical, lighting and industrial projects.

1. Basic Information

Item	Specification
Material Type	Borosilicate Glass
Brand	Corning®
Grade	PYREX® 7740
B₂O₃ Content	≈ 13 wt%
Density	2.23 g/cm³

2. Thermal Properties

Item	Specification
CTE (0–300°C)	3.3 × 10⁻⁶ /°C
Softening Point	≈ 820°C
Annealing Point	≈ 565°C
Strain Point	≈ 515°C
Thermal Conductivity	1.13 W/(m·K)

3. Mechanical Properties

Item	Specification
Young’s Modulus	63 GPa
Shear Modulus	26.1 GPa
Poisson’s Ratio	0.20
Knoop Hardness	≈ 480 kg/mm²
Flexural Strength	≈ 69 MPa

4. Optical Properties

Item	Specification
Refractive Index @ 587.6 nm	1.474
Abbe Number	65.7
Transmission Range	300–2500 nm (typical)
Appearance	Transparent, Colorless
UV Transmission	Limited below 300 nm

5. Chemical Properties

Item	Specification
Water Resistance (DIN ISO 719)	Class HGB 1
Acid Resistance (DIN 12116)	Class S 1
Alkali Resistance (DIN ISO 695)	Class A 2
HF Resistance	Poor, attacked by HF
Overall Chemical Durability	Excellent

6. Typical Applications

Field	Application
Laboratory	Beakers, flasks and lab glassware
Industrial	Sight windows and process vessels
Medical	Pharmaceutical packaging and devices
Optics	Optical windows and filter substrates
Lighting	High-temperature lamp envelopes

7. Borosilicate Glass — Grade Comparison

Property	Corning® PYREX® 7740	SCHOTT® BOROFLOAT® 33	SCHOTT® Duran®
Material Type	Borosilicate Glass	Borosilicate Glass	Borosilicate Glass
B₂O₃ Content	≈ 13 wt%	≈ 13 wt%	≈ 13 wt%
CTE (0–300°C)	3.3 × 10⁻⁶ /°C	3.25 × 10⁻⁶ /°C	3.3 × 10⁻⁶ /°C
Softening Point	≈ 820°C	≈ 820°C	≈ 825°C
Density	2.23 g/cm³	2.20 g/cm³	2.23 g/cm³
Refractive Index (nd)	1.474	1.471	1.473
Production Method	Rolled / Drawn	Float Process	Drawn / Tubing
Surface Flatness	Standard	Excellent (float surface)	Good
Brand Origin	USA	Germany	Germany
Industry Strength	Lab & Medical & Industrial	Semiconductor & Precision Optics	Lab & Pharma & Tubing

Corning® PYREX® 7740 Borosilicate Glass

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