A syndiotactic polystyrene-toluene solution was cast under two different casting conditions to obtain the delta form. A systematic study of its conformational transition, thermal behavior, and structural transformation as functions of the annealing temperature and time was performed. Spectroscopic studies revealed the content of its helical conformations and its retention up to 190 degreesC. Thermal analyses showed a significant difference in the transformation from the gamma form to the a form. The retention of the intermediate emptied clathrate form (mesophase) of the conformational order for a longer duration (from 120 to 180 degreesC) in a syndiotactic polystyrene membrane cast at room temperature was confirmed by X-ray diffraction analysis. On the basis of the experimental results in this work, the transition mechanism is discussed.