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The local and cooperative dynamics in atactic (a-PS) and syndiotactic (s-PS) polystyrene were studied by broadband dielectric spectroscopy. Besides the known R-relaxation, two additional relaxation processes β 1 and β 2 were revealed in various samples of a-PS and s-PS films cast from solvent solutions. These new dynamic processes show Arrhenius behavior, a common activation energy around 80 kJ/mol, and cross the R-relaxation region without merging, indicating a molecular origin being phase-separated from the amorphous PS fraction. By Fourier transform infrared spectroscopy (FTIR) measurements, a clear link between the existence of T 2 G 2 helix conformation and the occurrence of the β 1 -and β 2 -processes was established. Symmetry arguments and systematic differences in the relaxation parameters between a-PS and s-PS favor the assignment of the fast, β 1 , process to a helix defect mechanism (helix inversion), while the slow mode, β 2 , likely originates from cooperative helix inversion events that would point to spatially organized aggregates of helices, as suggested earlier for PS gels. The occurrence of such solvent-induced structures and their dynamics might have important implication for the interpretation of T g reductions found in ultrathin PS films.