Thermomicrohardness analysis (TμHA) of glassy materials

A thermal analysis technique and an apparatus are described which are used to study phase transformations in glassy materials by monitoring the temperature dependence of the microhardness through a phase transformation with the heating rate varied as a parameter. The method has been named Thermomicrohardness Analysis (TμHA). The glass transformation behaviors of a-As₂Se₃ xerographic photoreceptor type films have been studied to elucidate the nature of structural changes in the glass transformation region of glasses. It is shown that on an Itoh-Shishokin plot the Vickers microhardness exhibits a sharp fall in the glass transition interval due to a relaxation phenomenon similar to the relaxation of the enthalpy as determined by DSC measurements. Furthermore it is shown that the relaxation rate in both the processes is inversely proportional to the instantaneous viscosity.