A non linear constitutive model is suggested for the thermoviscoelastic materials that undergo varying temperature histories.The description of the model is based on the concepts similar to those in a linear thermoviscoelastic model,such as relaxation surface at constant temperatures,relaxation curve along a varying temperature history and equivalent relaxation curve in the terminal temperature plane.The non linear model has been applied to the simulation of deformation of the molds of CRT glass bulb.The numerical results show better agreements with the measured data of the molds than the ones based on the linear model.
