Effect of network connectivity on thermal properties of As30Te70– x Tl x glasses

Abstract

Alternating differential scanning calorimetry (ADSC) studies were undertaken to investigate the effect of Tl addition on the thermal properties of As30Te70– x Tl x (6 ≤ x ≤ 22 at%) glasses. These include parameters such as glass-transition temperature (T g), changes in specific heat capacity (ΔC p) and relaxation enthalpy (ΔH NR) at the glass transition. It was found that T g of the glasses decreased with the addition of Tl, which is in contrast to the dependence of T g in As–Te glasses on the addition of Al and In. The change in heat capacity ΔC p through the glass transition was also found to decrease with increasing Tl content. The addition of Tl to the As–Te matrix may lead to a breaking of As–Te chains and the formation of Tl+Te−AsTe2/2 dipoles. There was no significant dependence of the change of relaxation enthalpy, through the glass transition, with composition.