The glass transition behaviour of polystyrene (PS) with systematically varied topologies (linear, star-like and hyperbranched) confined in nanoscalic films was studied by means of spectroscopic vis-ellipsometry. All applied PS samples showed no or only a marginal depression in glass transition temperature T(g) in the order hyperbranched PS (5 K)> starlike PS (3 K) > linear PS (0 K) for the thinnest films analyzed. The T(g) behaviour was accompanied by the observation of the film density in dependence of film thickness. A maximum decreased density of about 7% for hyperbranched PS and 5% for star-like PS and again no deviation in density of bulk was found for linear PS. Accordingly, we deduce from these results considering an experimental accuracy of about +/- 2 K for T(g) and up to +/- 3% for film density, that the polymer topology only barely influences T(g) in the confinement of thin films. (C) 2010 Elsevier Ltd. All rights reserved.