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PYREX® Borosilicate Glass

Temperature resistant technical glass PYREX® 7740

Special Properties

  • High thermal resistance
  • Low thermal expansion
  • Good thermal shock resistance
  • Thermal expansion matches silicon (anodic bonding)
  • Low specific weight

Typical Applications

  • Glass substrates for dielectric coatings
  • PYREX® Wafers for anodic bonding
  • Sensor substrates
  • Heat shields and covers
  • Neutron absorber glass
  • High temperature applications
  • Harsh environments
  • Chemical laboratory applications
PYREX borosilicate glass raw blocks nullspacer Unprocessed PYREX® borosilicate glass comes in unpolished large glass blocks or as rolled glass. It can be sawn, ground, polished and shaped according to customer-specific requirements.

PYREX® 7740 borosilicate glass is a technical glass composition from Corning with excellent thermal properties. A low coefficient of thermal expansion which is nearly only one third of what ordinary soda lime glass can offer, allows a good heat shock resistance and facilitates the use of PYREX® glass at a high operating temperature. Wafers made of PYREX borosilicate glass are an ideal solution for PYREX unpolished borosilicate glass raw material from Corninganodic bonding processes, because the thermal coefficient of expansion almost perfectly matches to silicon. A good chemical resistance, which is also much better than the one of soda lime glass, and a high optical transmission over a wide wavelength range, make PYREX® borosilicate glass a versatile option for many different special glass applications that are not possible with soda lime glass materials. PYREX® glass can be ground, polished and coated according to custom specific requirements.

In order to request a quotation for windows or substrates of PYREX® borosilicate glass with individual dimensions, please use the button below:

Request for Quotation


Note: The production of PYREX® 7740 borosilicate raw glass has been discontinued by Corning many years ago. There is only a small remaining stock existing, so large quantities cannot be offered based on this glass anymore. Nevertheless we have equivalent or superior borosilicate glass materials available that feature an almost identical glass composition and almost identical or better specifications. Please send us your inquiry. We will be pleased to assist you in the selection of the right replacement glass type for PYREX® 7740 borosilicate glass that fits your individual application.

Specifications of PYREX® Borosilicate Glass

Show transmission curve of PYREX®

Refractive Index

  • nd = 1,474 (588nm)


  • 2,23g/cm3

Coefficient of Thermal Expansion (0-300°C)

  • 3,25 x10-6

Young's Modulus

  • 6400 kg/mm2

Dielectric Constant

  • 4,6 (20°C; 1Mhz)

Loss Factor

  • 0,5% (20°C;1Mhz)

Further detailed glass specifications on request.

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