Reinterpretation on configurational entropy of glass

Abstract

There is a long-standing controversy on the residual entropy of glasses. As a contribution to the residual entropy debate for glasses, the configurational entropy of an Ising-type model is evaluated in non-equilibrium from thermodynamic (calorimetric) formula and the other based on statistical thermodynamics. And then the values are compared quantitatively. It is shown that the statistical thermodynamic entropy becomes greater than the calorimetric entropy upon cooling so that the real residual entropy is greater than the calorimetrically estimated value, at least the value is non-zero. Moreover, the statistical thermodynamic entropy which originated from macroscopic ‘thermodynamic degeneracy’ is thought to be a good approximation to the thermodynamic (valorimetric) entropy originated from microscopic structural disorder. Finally, it is concluded that non-zero entropy value is a real entity and it has the useful physical and chemical meanings in real crystal and glasses.