Thermodynamic and Kinetic Characteristics of Glass Transition in an Amorphous Alloy Pd_77.5Ni_6.0Si_16.5

Variation of some thermodynamic functions of an amorphous alloy Pd_77.5Ni_6.0Si_16.5 in glass transition temperature region during various scans was measured by a differential scanning calorimeter. The Gibbs free energy of glassy state was examined to be larger than that of the undercooled liquid state when the specimen was heated up to the glass transition temperature region, which supports the idea of what there are thermodynamic origins underlying glass transition process. On the other hand, it was found that glass transition behaved differently during heating and cooling scans. Moreover, with increase of heating rate, the glass transition process was delayed gradually to higher temperatures. It can be concluded that glass transition is a kinetically modified thermodynamic phase transformation.