Ge42–xPbxSe58 (9≤×≤20) glassy alloys have been prepared using melt quenching technique. The samples were then subjected to differential scanning calorimetry (DSC) for recording the phase transformation occurring in the samples as a function of temperature. The characteristic temperatures of transformation, i.e. glass transition temperature, Tg, and crystallization temperature, Tc, were extracted from the DSC scans. The values of Tg and Tc were further used to ascertain thermal stability of the prepared glassy samples using Dietzel (ΔT) stability parameter. The variations of Tg with average coordination number, , were specified. It was found that ΔT exhibited a maximum at =2.44, close to the critical coordination number =2.40 optimized for maximum stability of glassy matrix. Thus, the obtained result follows Phillips-Thorpe constraint theory where the maximum stability of the network is just obtained if the percolation threshold limit is reached. The overall mean bond energies of the gl...

Stability and Percolation Threshold of Ge42–xPbxSe58 (9≤×≤20) Glasses

Chemical thermodynamics is finding increasing application in glass science and technology. It results from the necessity to realize in a deeper way the nature of glass and the phenomenon of glass transition, as well as from the development of modern methods of optimization of technological processes using electronic computers.In the field of glass science and technology all the main aspects of chemical thermodynamics are used. They will be briefly outlined.

M. M. Shultz

Papers

Thermodynamics of Melts and Glasses