Unlike conventional glass, quartz glass does not contain calcium oxide or soda, but consists of pure silica (SiO2). In industrially produced quartz glass, a distinction is made between natural (“fused quartz”) and synthetic (“fused silica”) origin. At Raesch, we use only natural primary materials with varying concentrations of impurities in the ppm range.

Quartz glass is produced by melting quartz sand of exceptional purity (SiO2 content of 99.98%) and then allowing the melt to cool and solidify.

Semi-finished goods made from quartz glass have many exceptional properties which make them ideal for high-quality products for a wide range of applications:

  • permeability for infrared to UV light (wavelength approx. 170 nm to 5,000 nm)
  • very high purity
  • excellent elasticity
  • high compressive strength
  • softening point is significantly higher than that of other glass types
  • extremely low thermal expansion coefficient
  • high thermal shock resistance
  • low thermal conductivity
  • essentially impermeable to gases
  • excellent optical transmission properties
  • exceptionally high chemical resistance
  • high resistivity
  • disruptive strength approx. 40 kV/mm
  • high dielectric strength

Our products are primarily used in lamp production and in the semiconductor industry.

In lamp production, quartz glass is predominantly used for UV and IR lamps, which require a high level of purity and high resistance to deflection. These properties contribute to the long service life of the lamps, even at high operating temperatures.

Leading semiconductor manufacturers all over the world use quartz glass in various ways in their production processes. The outstanding properties of quartz glass here are its high chemical purity, its high thermal resistance and precise dimensional tolerances. Due to its exceptional purity, quartz glass is almost free of impurities such as metals which would be harmful for the semiconductor components. Constant further development as regards the purity and dimensions of our quartz glass products ensures that we can continue to offer optimum solutions, e.g. for the semiconductor industry, in the future.