| Abstract: | The dielectric behavior of a low molecular weight fraction of poly(diethylene glycol terephthalate) has been studied over the frequency range 102 to 105 Hz for temperatures between ?67 and +51°C. Two relaxations, α and β, which exhibit pseudoactivation energies of 52 and 8 kcal/mole, respectively, have been found. The α relaxation, associated with the glass transition of the polymer, is amenable to a Williams–Landel–Ferry (WLF) analysis. The dipole moment ration 〈μ2〉/Nm2 (where 〈μ2〉 is the mean square dipole moment of a chain consisting of N bonds and m2 is the average of the squares of the bond moments) has also been calculated using the dielectric data obtained for the polymer in the undiluted state. The calculations yield 〈μ2〉/Nm2 = 0.710, a value in very good agreement with that obtained from measurements in solution. |
