Effect of topological thresholds on thermal behaviour of germanium telluride glasses containing metallic additive

Differential Scanning Calorimetric (DSC) studies on Ag<Subscript>x</Subscript>Ge<Subscript>15</Subscript>Te<Subscript>85-x</Su bscript> glasses have been undertaken over a wide range of compositions, to understand the effect of topological thresholds on thermal properties. It is found that the compositional dependence of glass transition temperature (T <Subscript> g </Subscript>), crystallization temperature (T <Subscript> c </Subscript>), activation energy for crystallization(ΔE) and thermal stability (ΔT) show anomalies at the rigidity percolation threshold. Unusual variations also observed in different thermal properties at the composition x=20, clearly establishes the occurrence of chemical threshold in these glasses. Copyright EDP Sciences, Springer-Verlag 1998