CHEMICAL ORDERING AND TOPOLOGICAL EFFECTS IN CHALCOGENIDE GLASS SYSTEMS

The property-composition data of several chalcogenide glass systems ha ve been summarised. Models such as the chemically ordered network mode l and the topological models which have been adopted to understand the atomic arrangement in network glasses are briefly reviewed. The merit s and the drawbacks of these models have been pointed out. The importa nce of considering the effects of both the chemical ordering and of ne twork topology in accounting for the features observed in the property -composition data of network glasses has been indicated.