The phenomenological theory using in phase transition of crystalline state is generalized to polymers. The dielectric behaviors and space charge electret effects of polymers in the process of its structural transitions are explained by the theory. The phase transition of a crystal is the transition of its structure of first-order, it is related to the anomalous of dielectric constant εh of fast polarization. But the structural transitions of a polymer is only the transition of its structure of second-order and third-order; in this process, the anomalous of εh absents and the reciprocal of dielectric constant εl of slow polarization softens as parabolic type. The theory is in good agreement with experimental results of polypropylene.
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