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PYREX® 7740

Heat-resistant borosilicate glass

Special Properties

  • High-temperature resistance
  • The coefficient of thermal expansion excellently matches silicon (important for anodic bonding applications)
  • Good thermal shock resistance
  • Small specific weight

Typical Applications

  • PYREX® wafers for anodic bonding
  • Glass substrates for dielectric coatings
  • Heat shields
  • Chemically resistant glass covers
  • Neutron absorber glass
  • High-temperature environments
  • Sensor technology
  • Applications in science, research, and development
  • Harsh Environments
  • Material for chemical laboratory equipment

Related glass types

PYREX® 7740 is a borosilicate glass from CORNING with excellent thermal properties. The material was an industry-standard used to manufacture glass wafers and temperature-resistant optics for a long time. A low coefficient of expansion, which is only about one-third of soda-lime glass materials, ensures excellent thermal shock resistance.

PYREX borosilicate glass raw blocks nullspacer

Unprocessed PYREX® comes in unpolished large glass blocks or as rolled sheet glass. We can saw, grind, polish, and process these borosilicate glass materials to customer-specific requirements.

Glass wafers made of PYREX® 7740 have long been a standard for the semiconductor industry. They were a perfect solution for the anodic bonding of glass to silicon because the low thermal expansion of PYREX® 7740 is close to silicon. A high chemical resistance much better than that of soda-lime glass and an excellent optical transmission over a wide wavelength PYREX unpolished borosilicate glass raw material from Corningrange made PYREX® borosilicate glass a versatile option for many optics applications that were not possible with soda-lime glass materials. PYREX® glass is ground, polished, shaped, and coated according to customer requirements.

To request a quotation for windows, substrates, glass wafers, or other optics made of PYREX® borosilicate glass with individual dimensions, please use the button below.


Request for Quotation


Availability note: The production of PYREX® 7740 brand borosilicate glass materials was discontinued by Corning many years ago. There is no remaining stock, so for this glass, quotes aren't possible anymore. Alternatively, we process similar and superior quality borosilicate glass materials like BOROFLOAT® and the precision glass MEMpax®  that feature an almost identical glass composition and nearly the same or even better properties.

For high-temperature requirements, please look at our quartz glass and fused silica materials. Please also look at our fused quartz with sight glass quality for high-temperature sight glass applications and send us your inquiry. We are pleased to help you select the best replacement glass for PYREX® 7740 borosilicate glass that perfectly fits your application.


Specifications of PYREX®

PYREX® Borosilicate Glass
Transmission at 2 mm thickness

Transmissivity of PYREX® 7740

Enlarge curve to show details

Glass Thicknesses

Since PYREX® is not available as blank sheet glass, there are no standard thicknesses. The glass thickness must, therefore, always be specified individually.

Refractive Index

  • nd = 1,474 (588 nm)


  • 2,23 g/cm3

Coefficient of Thermal Expansion (0-300°C)

  • 3,25 x 10-6

Young's Modulus

  • 6400 kg/mm2

Dielectric Constant

  • 4,6 (20 °C ; 1 MHz)

Loss Factor

  • 0,5% (20 °C ; 1 MHz)

Further detailed glass specifications available on request.

All given details and specifications are mean reference values and are not guaranteed. Also, please consider our "Notes on technical specifications".

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