An analysis of the nonequilibrium thermodynamics of a dissipative system, dealt with at the mechano-statistical level provided by informational-statistical thermodynamics is presented. We consider in particular the case of a highly excited photoinjected plasma in a polar semiconductor. Under continuous constant illumination, a steady state sets in, whose macroscopic state is characterized, the main mechanisms for pumping and dissipation that are involved are analyzed, and the characteristics of the evolution towards the steady state and its stability are discussed. It is shown that such evolution displays a phenomenon of quasitemperature overshoot.23541732345368