Thermally induced photodegradation reactions occurring particularly in solid state are of great interest in materials science due to their crucial applicability in the field of solar materials for renewable energy purposes. Kinetic modeling of these reactions is helpful to evaluate the thermal stabilities and lives of solar materials which in turn play an important role in determining the efficiency parameters of these materials. However, it is a misfortune that the available kinetic methods to simulate these reactions are too oversimplified to deal with the well known complexity of these reactions. In this paper, a new systematic kinetic approach to model the thermally stimulated photodegradation reactions has been put forward for the first time. The determinancy of the kinetic parameters and the efficacy of the proposed kinetic approach under isothermal/non-isothermal conditions and simple/complicated photodegradation reactions are theoretically justified. On the basis of this new approach, an explicit formula to estimate the thermal stabilities/lives of the solar materials is suggested.