Relaxation of Chain Extension of Amorphous PET Fiber Above the Glass Transition Temperature

The recovery of amorphous PET fiber in global chain orientation but nearly random segmental orientation (GOLR) state was studied by the hot shrinkage measurement above the glass transition temperature. The relaxation curves in the form of di-exponential decay were acquired and the change of two special times with the variation of treating temperature and residual recovery ratio ' was discussed.