Glass transition temperatures of polymer thin films monitored by Raman scattering

We report measurements of the glass transition temperature (Tg) in thin free-standing polymer films of polystyrene (PS) by means of confocal Raman spectroscopy. The paper introduces Raman spectroscopy as a novel method for the determination of Tg in polymer thin films. We find excellent agreement between Raman scattering and previously reported values of Tg obtained from either Brillouin scattering or ellipsometry. Further possible applications of the method to more complex conjugated polymers are briefly discussed. 1. Introduction an