Modeling strategies to predict the viscoelastic behaviour of amorphous glassy polymers

We have recently reported that the phenomenological intricacies of mechanically stimulated glasses, even in their subtle features, can be reliably predicted by coupling the structural relaxation kinetics and viscoelastic response [1]. Simulations are obtained linking the modified KAHR equation with the constitutive equation for linear viscoelastic materials written in the reduced time domain. The model requires the knowledge of the "linear' shear and bulk relaxation functions, the factors that alter the responses timescales being encrypted into the definition of the reduced (or material) time. Here it will be shown analytically that the dimensionless bulk compliance coincides with the memory function appearing in the modified KAHR equation, so that, it can be extracted directly from the experimental PVT data. We conclude that the timescales of mechanically stimulated glasses are T already encrypted into the PVT and the shear relaxation behavior. Furthermore, it has assumed that the relaxation times scale with TV as recently proposed for many glass-formers [2].