The thermodynamic properties and the morphology of syndiotactic polystyrene solid samples exposed to solvents (benzene and toluene) are investigated. It is shown that, as far as the melting properties are concerned, there is no significant difference between these samples and solution-cast samples. This suggests that compound formation is a near-equilibrium process in these systems. Conversely, the morphology depends on the sample thickness. Fibrillar networks are obtained with thin films as opposed to the various morphologies observed for bulk samples.