Studies of the gamma ->alpha transition in syndiotactic polystyrene

In this work we compare calorimetric and X-ray diffraction experiments real ized on annealed sPS in helical gamma forms resulting by different treateme nts: from clathrate delta form and from interaction of amorphous sample wit h acetone. The experimantal results show that the gamma form obtained by ac etone converts into the more ordered final alpha " form modification; while the gamma form, obtained by thermal treatments of delta form, transforms i nto the poorly ordered final alpha' form.