Structural characterization and topological threshold in chalcogenide GexSb40-xSe60 glasses

The compositional dependences of some basic thermal properties of bulk GexSb40-xxSe60 glasses have been evaluated, taking into consideration the average coordination number (Z). In particular, the glass transition temperature (Tg), softening temperature (Ts), coefficient of thermal expansion in glass (alphag), specific heat capacity (DeltaCp) and .fragility (m) have been investigated by a complex application of differential thermal and thermomechanical analyses, X-ray diffraction and differential scanning calorimetry as well. The obtained peculiarities in their change at Z - 2.67 have been discussed in terms of topological structural transitions in chalcogenide glasses.