Ga-Ge-Sb-Se based glasses and influence of alkaline halide addition

The quaternary Ga-Ge-Sb-Se system has been systematically studied and the glass-forming region has been determined. It has been found that there is a domain in which glasses do not crystallise when heated at a rate of 10 degrees C/min. Optical properties of these glasses have been determined, showing transmission from 0.9 to 15 mu m. The refractive index for the Ga5Sb10Ge25Se60 glass is 2.6709 +/- 0.0001 at 2 mu m and 2.6198 +/- 0.00025 at 12 mu m. Some attempts have been made to increase the band-gap by introducing 5-30 wt% of electronegative elements such as Cl-2, Br-2 or I-2 in the form of alkaline halides. Refractive indices, optical transmission and chemical durability towards air and hot water of these new glasses have been measured. Results have been obtained with CsI addition and stable red coloured glasses have been synthesised, which are transparent to 14 mu m. (C) 1999 Published by Elsevier Science B.V. All rights reserved.