The dielectric loss spectra of poly (ethylene 2, 6-naphthylene dicarboxylate)(PEN) and several copolymers of 2, 6-naphthylene dicarboxylic acid and terephthalic acid with ethylene glycol have been studied over a wide range of frequency and temperature. Previously, Ezquerra, Balta-Calleja, and Zachmann have reported the presence, in isochronal temperature scans of dielectric loss, of a subglass process (β*) in PEN homopolymer in ...
