Quartzglas

Quartz glass, commonly referred to as fused silica, is an amorphous form of silicon dioxide (SiO2) produced by melting high-purity silica and forming a non-crystalline solid. It is distinct from crystalline quartz, which has a regular lattice structure.

Key properties of quartz glass include very high purity and chemical inertness, exceptional thermal stability with a very low coefficient of thermal expansion, and high softening temperatures. It remains transparent over a wide spectral range from the ultraviolet into the near-infrared, with a refractive index around 1.44–1.47 and a high Abbe number, indicating low chromatic dispersion. The material is brittle like other glasses but can tolerate high temperatures and aggressive chemical environments; hydrofluoric acid readily attacks silica, while many other acids and bases do not. Different grades exist, including low-OH (OH-free) and high-OH variants, which affect ultraviolet transmission.

Manufacture and forms: fused silica is produced by flame fusion or electric-arc melting of silica and then drawn or formed into components such as panes, tubes, lenses, and crucibles. Synthetic quartz, a crystalline form, is grown by hydrothermal or related processes and is used where crystalline properties are required. In German contexts, “Quarzglas” typically refers to fused silica, though terminology can vary.

Applications: quartz glass is widely used in optics (lenses, windows, prisms, photomask substrates), UV lithography, fiber optics, semiconductor processing equipment, labware (cuvettes, reaction vessels), and high-temperature or chemically aggressive environments.