Effect of atmosphere on reductions in the glass transition of thin polystyrene films

We have used nulling ellipsometry to measure the glass transition temperature, Tg , of thin films of polystyrene in ambient, dry nitrogen, and vacuum environments. For all environments, the measured Tg values decrease with decreasing film thickness in a way that is quantitatively similar to previously reported studies in ambient conditions. These results provide strong reinforcement of previous conclusions that such reduced Tg values are an …