Pyrex

  Corning's glass code #7740 glass is borosilicate composition that is used in the PYREX brand products to provide unique chemical, thermal, mechanical, and optical properties.  These properties enable it to provide long service and fulfill requirements which common window or container glass cannot meet.

Thermal Expansion x 10^-7 cm/cm/ C (0-300 C)

32.5

Strain Point, C

510

Annealing Point, C

560

Softening Point, C

821

Density g/cc

2.23

Dielectric Constant (1 MHz, 20 C)

4.600

Refractive Index @ 589.3 nm

1.473