PROPERTIES OF CHALCOHALIDE GLASSES IN THE GE-AS-SE-TE-I SYSTEM

Chalcohalide glasses have received more and more attention in recent y ears in their applications as optical materials transmitting in mid-fa r-infrared region because they share the advantages of chalcogenide an d halide glasses. In the present paper a series of properties of the n ovel chalcohalide glasses in As2Se3-GeTe-AgI system, such as transitio n temperature, density, microhardness, thermal expansion coefficient, electrical conductivity, chemical durability and infrared optical prop erties, were presented and discussed in detail in terms of structural variations induced by AgI doping. Agr acted as a network terminator in the chalcohalide glass, making a more open network structure by produ cing the one coordinated nonbridging I atom as well as some nonbridgin g Se and/or Te. These structural variations resulted in the decreases in T-g, H-v and chemical durability and the increases in a and cr and were also associated with the slight shift of infrared cut-off edge to wards the longer wavelength. The infrared cut-off wavelength of the pr esent ternary glasses is about 19 mu m.