The relaxation behaviors of PET film in NaOH solution were investigated in view of chemorheology under the various temperatures and those of the film with draw ratio and temperatures were examined phenomenologically in relation to the decomposition effect of NaOH. As the experimental results, the initial relaxation stress was decreased and relaxation rates rfrb were increased with temperatures at constant draw ratio. The relaxation spectra were composed of box and wedge types distribution and the relaxation time t1,t2 from constitutive eq. were shifted to a shorter time side with temperatures.