Fused silica glass uses
Fused silica and quartz are used in the manufacture of many optical components: such as optical lenses, optical mirrors, UV and IR wavelength transmitting optics, and metrology components—due to their ability to transmit light in the VIS(400-700nm), UV (200-400nm), and IR(700-14000nm) range.

Thermal Properties of Fused Silica

Thermal Properties
50℃-200℃ Linear thermal expansion coefficient			5× 10-7 cm/cm℃
Annealing point			1100±20 ℃
Softening point			1600±25 ℃
Strain point			1000±20 ℃
Mean specific heat			0.177
Heat conductivity(25℃)			3.3× 10-3 cal cm/cm2 sec℃

Highly Recommended Fused Silica Windows from Yutai Optics:
Optical Fused Silica Windows
Rectangular Fused Silica Windows with Round Corners
Fused Silica Windows with Step
Coring Series Fused Silica Windows
Thin Fused Silica Glass Sheet