Precursors of crystallization via density fluctuations in stiff-chain polymers

The ordering process just before cold crystallization for a stiff-chain polymer is studied by means of simultaneous real time wide- and small-angle x-ray scattering and dielectric spectroscopy techniques. The kinetics of the ordering process prior to crystallization is described by the spinodal decomposition formalism. From wide-angle x-ray scattering measurements it is confirmed that no crystalline order takes place during the induction period. The dielectric study of the alpha relaxation suggests that during this induction period there is not a major restriction of segmental motions of polymer chain segments.