The dynamical aspects of solid-solid phase transformations are studied within the framework of the theory of thermoelasticity. The main purpose is to analyze the role of temperature in the theory of phase transitions. This investigation consists of two parts: first, it is shown that by imposing a kinetic relation and a nucleation criterion it is possible to single out a unique solution to the Riemann problem for an adiabatic process. This extends to the thermomechanical case results previously found in a purely mechanical context. Secondly, based on an admissibility criterion for traveling wave solutions within the context of an augmented theory that includes viscosity, strain gradient and heat conduction effects, a special kinetic relation is derived using singular perturbation techniques