Measurement of Orientation Relaxation Process as a Method to Study Polymer Chain Dynamics

Time evolutions of orientation function f(t) of uniaxially stretched polystyrene films were measured in temperature region higher than the glass transition temperature Tgby polarized Fourier transform infrared spectroscopy (FT IR). Time temperature superposition principle was valid for the data of f(t) obtained at T=108–130°C. From the observation of the master curve of f(t), it was found that the relaxation in time region from glass transition to the biginning of terminal flow can be observed. Further, from a comparison between f(t) and stress relaxation elastic modulus E(t), it was shown that the same information obtained by rheological measurement in non-linear region can be obtained by observation of f(t).