利用X射线小角散射和广角衍射技术,研究了晶胞体积、散射积分不变量Q和长周期在α和β松弛过程中的变化,发现晶体结构的演变与非晶区的α和β松弛有较强的关联性,而且不同相区在高分子松弛变化过程中具有协同性.结果表明,晶胞体积变化在高分子链段运动的α松弛和主链基团扭转的β松弛的激活和冻结过程中是可逆的.由于系带分子的β松弛行为被冻结或激活而引起晶胞体积收缩系数的改变,从而导致晶胞体积在-90℃出现突变.散射积分不变量Q在整个过程中也是可逆变化的,在可逆过程中发生的突变主要是由于α松弛的冻结或激活引起的.因为样品在降温过程中发生插入式的结晶模式,在升温过程中这些二次结晶形成的片晶需要在较高温度下才能熔化,所以在整个过程中长周期变化不可逆.
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