A new constitutive model is derived for the viscoelastic behavior of polymers under non-isothermal loading. The model extends the Tobolsky concept of adaptive links (entanglements) between polymeric molecules to thermoviscoelastic media. Employing this model, we calculate residual stresses built up in an epoxy resin plate under cooling from the rubber-glass transition temperature, analyze the effect of material parameters on residual stresses, and compare results of numerical simulation with experimental data.