Dynamics near the Glass Temperature of Low Molecular Weight Cyclic Polystyrene

The segmental relaxation properties of a low molecular weight (4.6 kg/mol), cyclic polystyrene (PS) were characterized. The sample was obtained by fractionation using HPLC at the chromatographic critical condition, which yields a ring uncontaminated by its linear precursor. Both the glass temperature and the temperature dependence of the segmental relaxation times for the ring PS were equivalent to the high molecular weight limiting values for the linear polymer. These results are interpreted by considering the configurational mobility of a polymer lacking chain ends.