Quartz glass preform for an optical element as well as process of manufacture and use thereof

摘要

Quartz glass blank comprises a glass structure having a hydrogen (H2) content of 0.1 x 10<16> to 4.0 x 10<16> molecules /cm<3>, an OH content of 125-450 wt.-ppm, an SiH group content of less than 5 x 10<16> molecules/cm<3>, an inhomogeneity of less than 2 ppm in the refractive index of DELTA n and a birefringence of less than 2 nm/cm. An Independent claim is also included for a process for the production of the quartz glass blank. Preferably the OH content of the glass blank is 200-350 wt.-ppm and the H2 content is 1 x 10<16> to 3 x 10<16> molecules /cm<3>