Thermal properties
Linear Thermal Expansion Coefficient

5.7 x 10-7 cm/(cm.°C) ( 20°C - 320°C)

Softening Point 1600 ± 25°C
Strain Point 1000 ± 20°C
Annealing Point 1100 ± 20°C
Max Service Temperature 1150°C - continuous
1300°C – limited time
Thermal Conductivity 1.38 W/(m.°C)
Specific Heat 0.177 cal/gm°C
Thermal Diffusion

7.5 x 10-3 cm2/sec

Mechanical properties
Density 2.20 g/cm3
Young’s Modulus 71.7 GPa
Bulk’s Modulus 37 GPa
Shear Modulus 31 GPa
Knoop Hardness 500 kg/mm2
Rupture Resistance 50 MPa @ 25°C
Poisson’s ratio 0.17 @25°C
Electrical properties
Electrical Resistivity > 1018 Ω x m
Dielectric Strength 250 - 400 kV/cm @ 20°C
Dielectric constant 3,75 @ 20°C 1 MHz
Resistivity 7 x 107ohm-cm @350°C
Optical properties
Transmission  Please see the graph below
Refractive Index 1.45840 @ 589.3nm
Transmission Curve


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