Alumino-boro-silicate glass and process to make crystal-free Gradient Index Lenses

摘要

In a process to make alumino borosilicate glass for the production of gradient index (GRIN) lenses, the glass has much reduced tendency to crystallisation in the subsequent thermal treatment processes. The base glass is a mixture of SiO2, Al2O3, a metal (III) oxide (of B and/or Ga) and a metal (I) oxide (of Li, Na, K and/or Rb). In the process the base glass as defined Mol ratios of metal (III) oxides to metal (I) oxides within a predetermined range.