Physical evolution in network glasses of the Ag–As–Te system

Abstract To understand the structural features of the Ag x As 50− x Te 50 , 3⩽ x ⩽20, glass system, various properties are separately studied as a function of the average coordination number 〈 r 〉 . The relation between the chemical ordered covalent network model and constraint theory were applied to investigate the structural features. The overall mean energy 〈 E 〉 , of a covalent network for the Ag–As–Te ternary glasses is determined and was found to decrease in the range 3.85–3.408 eV. The average coordination number 〈 r 〉 has been examined for the Ag–As–Te system in the light of recently suggested models for network glasses. In addition, the two topological effects, namely; the floppy to rigid transition and the structural transition occurred and resulted in some changes in chemical ordering. The values of the glass transition temperature T g were found to depend on the composition showing a decrease from 170 to 130 °C with increase in Ag content. The thermal stability and the glass-forming tendency are calculated and they were found to have the same trend.