In this work Raman spectroscopy was employed for the detection of the glass transition temperatures (Tg) of some thermoplastic polymers and natural terpenoid resins. In particular, our attention was focused on evaluating the Tg of polystyrene and colophony. The measurements returned Tg values in accordance with those reported in the literature obtained using the DSC technique, thus confirming the reliability of the approach proposed herein. Further studies will be focused on the evaluation of Tg temperature changes depending on materials treatments and ageing.