Summary: Isothermal crystallization of an oriented blend of isotactic polystyrene (iPS) with poly(2,6‐dimethyl‐1,4‐phenylene oxide) (PPO) was studied by in situ polarized FT‐IR spectroscopy and wide‐angle X‐ray diffraction. The structural organization during the oriented crystallization consists of three stages. The first stage is the orientation relaxation of molecular chains of iPS and PPO, the degree of orientation of iPS increases in the second stage, and the oriented chains of iPS crystallize in the third stage.
