Thermodynamic parameters of bonds in glassy materials from shear viscosity coefficient data

Abstract

A simple analytical approach is proposed that provides numerical values of thermodynamic parameters of bonds (enthalpy and entropy of formation) in glassy materials from four shear viscosity coefficient data at four temperatures, two of which should be below Tg and other two above Tg. This method replaces complex fitting procedures for the nonlinear viscosity equations to experimental data and provides accurate data close to that obtained from fitting procedures. It can be also used for obtaining zero estimates of unknown parameters for the nonlinear least squares regression procedures. © 2014 The American Ceramic Society and Wiley Periodicals, Inc.