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
  • Substrates for dielectric coatings
  • Heat shields
  • Chemically resistant glass covers
  • Neutron absorbers
  • High-temperature environments
  • Sensor technology
  • Applications in science, research, and development
  • Harsh Environments
  • Material for chemical laboratory equipment

Related glass types

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

PYREX borosilicate glass raw blocks nullspacer

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

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


Please use the button below to request a quotation for windows, substrates, wafers, or other optics made of PYREX® with individual dimensions.


Request for Quotation


Please look at our quartz and fused silica materials for higher-temperature requirements. Also, fused quartz with sight glass quality is available.


Specifications of PYREX®

PYREX® Transmission at 2 mm thickness

Transmissivity of PYREX®

Enlarge curve to show details

Glass Thicknesses

Since PYREX® is not available as blank sheet glass, there are no standard thicknesses. The 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 × 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 are 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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