Amorphous syndiotactic polystyrene (sPS) films were annealed at 110 de
grees and 115 degrees C for 24 h. The annealing at the higher temperat
ure produced the mesomorphic form of sPS, characterized by conformatio
nal order, as shown both by the presence of the zigzag band in the inf
rared spectrum and by the presence of characteristic peaks in the x-ra
y diffractogram. The crystalline form was riot formed at the investiga
ted temperatures. Differential scanning calorimetry of the mesomorphic
sample shows that the transformation of the mesophase into the crysta
lline phase occurs during the heating run. The transport properties of
dichloromethane show that the mesophase is impermeable to the vapors
at low activity and becomes permeable at higher activities. At low act
ivity it is therefore possilble to derive the fraction of impermeable
phase, which corresponds to the fraction of mesophase. This fraction w
as about 50%.