Physical properties of chalcogenide and chalcohalide glasses

The physical properties of glasses in the Ge30As10Se((60-x))Te(x) system wi th x = 25, 28, 30, and 35 at.% Te, the Ge(30)As(10)Se(30)Teo((30-y))I(y) sy stem with y = 5, 10, 20, and 30 at.% I, the Ge30As10Se35Te(25-z)Iz system w ith z = 2, 6, 10, and 20 at. % I, and the [Ge30As10Se30Te30]((100-w))I-w sy stem with w = 0, 5, 10, and 20 at,% I have been investigated. The changes i n the glass transition temperature, density, coefficient of thermal expansi on, hardness, and viscosity are attributed to the delocalized metallic bond ing character of Te in the substitution of Te for Se in the Ge-As-Se-Te gla ss system and the network-terminating role of iodine in the substitution of I for Te in the Ge-As-Se-Te-I glass system, respectively.