Preparation of oriented thin films of a series of soluble conjugated polymers and characterization of linear and nonlinear optical properties is described and discussed. The orientation of polymer chains leads to an enhanced cubic susceptibility, important for the targeted practical applications of these materials. The refractive indices and the optical birefringence of thin films were determined using the m-lines technique. The nonlinear optical properties were measured by optical third harmonic generation technique and by picosecond z-scan method. The figures of merit for the application of PPV-MDMO polymer in all optical switching are derived. The kinetics of chemical degradation of a conjugated p electron polymer was also studied and the degradation rate was measured.