In recent years, Light curing mechanism can be applied in many applications such as dental restorations, medical treatment, LED packaging, self-written waveguide, etc. In this dissertation, the modeling of polymerization of various application is presented. We also discuss the temperature how to influence the photoinitiation rate, and the uniformity of the polymerization. Furthermore, the kinetics of photoinitiated polymerization for active packaging of light-emitting diodes (LEDs), and self-written waveguides is presented thoroughly. The light propagation behavior can be expressed by beam propagation method, and the light distribution emitted from LED chip can be expressed by integrating the infinitesimal emitting area on the LED surface. Then we provide a simulation process based on finite difference method to solve the mechanism between the light absorption and polymerization reaction. The time-evolution of the polymer profile during polymerization can be analyzed as the monomer concentration varies. The proposed technique can depict the shape and precise size of the polymer for any specific parameters in the polymerization reaction, e.g., LED power or laser beam intensity, polymerization time, absorptivity of the epoxy and photolysis. Polymerization experiments for LED packaging and self-written waveguides with different light intensity, polymerization time were made to support our simulation results, and the simulation results agree well with the experiment results.