Observation of a fast dielectric relaxation in semi-crystalline poly(ethylene oxide)

Our broadband dielectric study has revealed for the first time a relaxation (termed γ′) between the low temperature β and γ-processes of semi-crystalline poly(ethylene oxide) (PEO). The activation energy of the γ′-transition is indicative of a local process, and this relaxation becomes broader with increasing temperature. We propose that this process is due to the motion of PEO segments in the transition region between PEO lamellae and disordered interlamellar amorphous segments. The unusual local character of the γ′-process is explained by analogy to the fast process or primitive α-relaxation in nanoconfined glass forming systems. This mechanism is supported by comparison of the dielectric behavior of samples with different thermal histories.