The growth and decay processes of the optically induced birefringence in an azobenzene-functionalized polymer, DR19FPOZ (full name given in the text), and in another azobenzene guest/host polymer system have been studied. The temperature dependence of the birefringence signal is studied, and possible mechanisms associated with the growth and decay segments of the signal are analyzed. Rate constants deduced from the optically induced birefringence signal are also investigated as a function of the laser excitation power and film thickness. The rate constants associated with the growth and decay processes and activation energies are obtained for the polymer system below the glass transition temperature.