In conclusion, our results demonstrated the use of THz spectroscopy for the observation gives direct information of the intermolecular dynamics than other spectroscopic methods, it is expected to become a novel method for the polymer structural analysis. Furthermore, THz spectroscopy enables in situ measurement for large samples. Unlike DSC or NMR, non-invasive spectroscopic imaging is possible to detect the water distribution in polymer products. Therefore, we expect that THz spectroscopy may be used as a novel diagnosis tool for polymer industries in the near future.