The dynamics of two main-chain nonlinear optical polymers, PA-PS and PA-MS, was studied at various temperatures below T-g. In the characterization, both the photo-induced isomerization method and second harmonic generation were employed. In the case of non-polar alignment by the linearly polarized UV light, the main-chain of PA-PS polymer was found well re-aligned but the main-chain of PA-MS polymer was not, because of the high rigidity. In the case of polar alignment by in-situ corona poling technique, double exponential Functions fit well to the data of both PA-PS and PA-MS polymer relaxation data at all the temperature range.