Fused silica glass is a form of non-crystalline silicon dioxide, produced synthetically by the vapor phase hydrolysis of a silicon halide. Fused silica is known as the purest form of glass and has many industrial uses due to its properties.
Mechanical Properties of Synthetic Fused Silica
Formula
SiO2
Solid State
Amorphous
Density (25°)
2.202 +/- .002 gm/cm
Refractive Index (632.8 nm)
1.457
Useful Optical Transmission Range
180-2500 nm
Water Absorption – Saturation
0%
Poisson’s Ratio
0.17
Elasticity (Young’s) Modulus (25°C)
745 x 10³ kg/cm²
Shear (Rigidity) Modulus (25°C)
320 x 10³ kg/cm²
Bulk Modulus (25°C)
420 x 10³ kg/cm²
Tensile Strength (25°C)
600 kg/cm²
Compressive Strength (25°C)
11.3 x 10³ kg/cm²
Hardness:
Knoop-KHm (100 gm load)
600 kg/mm²
Moh
7
Sonic Properties of Synthetic Fused Silica
Velocity of Sound:
Shear Wave
3.75 x 10³ m/sec
Compressional Wave
5.70 x 10³ m/sec
Ultrasonic Velocity (50°C):
Shear Wave
3.75 x 10³ m/sec
Compressional Wave
5.95 x 10³ m/sec
Temperature Coefficient of Ultrasonic Velocity:
Compressional Wave (°C⁻¹)
81.5 x 10⁻⁶
Sonic Attenuation
> .11 db/mMhz
Internal Damping
1 x 10⁻⁵
Chemical Properties of Synthetic Fused Silica
Resistance:
Acids – Concentrated
Good
Acids – Dilute
Good
Alkalis
Fair
Halogens
Good
Metals
Fair
Electrical Properties of Synthetic Fused Silica
Dielectric Strength:
25° C
300-400kV/cm
500° C
150-200 kV/cm
Dielectric Constant
3.8
Electrical Properties of Synthetic Fused Silica at 25° C
100 Hz
1 KHz
10 KHz
100 KHz
1 MHz
10 MHz
100 MHz
8.6 GHz
24 GHz
Dielectric Constant
3.826
3.826
3.826
3.826
3.826
3.826
3.826
3.824
3.82
Loss Tangent
<.000004
<.000002
<.000005
0.00001
0.000015
0.00002
0.00003
0.00012
0.00033
Volume Resistivity Log10R, ohm-cm
>15.0
>14.3
>12.9
11.7
10.5
9.34
8.2
5.65
Measurement performed at Laboratory of A.R. Von Hippel, Laboratory for Insulation Research, Massachusetts Institute of Technology, May 1970.
