Reversibility in glass transition behavior after erasing stress induced by spin coating process

Abstract The influence of the sample preparation on the observed dependence of glass transition temperature ( T g ) with thickness in polystyrene (PS) thin films has been investigated. Spectroscopic ellipsometry was used to measure the T g of PS thin films ranging from 7 to 85 nm before and after exposition to supercritical carbon dioxide (sc-CO 2 ). We take advantage of the sc-CO 2 properties along with thermal annealing treatment to cancel out sample preparation history factor by removing the remnant solvent and residual stresses. The decrease in T g shows exactly the same trend before and after sc-CO 2 exposure plus thermal treatment. This result cancels out the influence of the spin coating process on the T g depression in thin films.