Tellurium and selenium halide-based glasses, their preparation and use

Abstract

Vitreous solid compositions of formula I: Te.sub.w Se.sub.y X.sub.x Z.sub.z (I) wherein X represents at least one halogen selected from chlorine, bromine and iodine, Z represents at least one element selected from As, Sb and Bi, w, x, y and z represent the molar percentages respectively of elements Te, X, Se and Z, w being a number varying from 5 to 50, x being a number varying from 5 to x.sub.1, y being a number varying from 5 to 80, z being a number varying from 5 to z.sub.1, the numbers w, x, y and z being such that the sum (w+x+y+z) is equal to 100, the numbers x.sub.1 and z.sub.1 being such that: when X represents mostly iodine, x.sub.1 =50 and z.sub.1 =60, when X represents mostly bromine, x.sub.1 =60 and z.sub.1 =50, and when X represents mostly chlorine, x.sub.1 =60 and z.sub.1 =40, it being understood that the molar percentage of Bi, when it is present, is not greater than 12 and that the molar percentage of the element Sb, when it is present, is not greater than 20; their preparation and their use principally in the field of infrared transmission.

Dependencies are inferred from the claim text.