CALPHAD modeling of the glass transition for a pure substance, coupling thermodynamics and relaxation kinetics

A coupled thermodynamic/kinetic CALPHAD type modeling of the glass transition for a forming unary substance is proposed. In this quantitative modeling, vibrational contributions to thermodynamic functions crystal and liquid/glass phases are classically modeled using weighed sums Einstein while configurational phase described single internal variable within frame ideal two-state model. The freezing kinetics on cooling calculated with an Adam-Gibbs logarithmic relaxation law. model applied boron oxide B2O3 and, after numerical optimization parameters, shown well represent hysteresis loop heat capacity detected by DSC in range during cooling/reheating cycles at various rates. also allows calculate fictive temperature residual or zero-point entropy glass.