The temperature drops in glassy polymers while strained

Constitutive equations are derived for nonisothermal loading of glassy polymers at finite strains. The model is based on the theory of temporary networks in a version of the concept of adaptive links. The specific mechanical energy of a temporary network is determined with account for the potential energies of deformation for individual links and the energy of interaction between them. Stress-strain relations and a differential equation for the evolution of temperature are obtained using the laws of thermodynamics. As examples, we study uniaxial extension of a bar and simple shear of a layer. Explicit formulas are derived for the temperature drops prior to necking of specimens. Good agreement is demonstrated between experimental data for polycarbonate at room temperature and predictions of the model.