ガラス転移温度以上において熱処理したポリエチレンテレフタレートガラスの構造緩和

概要

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Isothermal volume contraction due to physical aging was measured for linear poly(ethylene terephthalate)(PET) glasses and for branched PET glasses of ethylene terephthalate-trimellitic(TMA) copolyesters. Materials were subjected to various thermal annealing treatments at temperatures above their glass transition temperatures (Tg), and then aged at temperatures ranging from Tg-10 °C to Tg with aging time ranging from 10 min to 7 days. Over the range of temperatures studied, normalized volume data for the annealed glasses could be superimposed using aging time-temperature superposition. The shape of reduced curves not to be described by a stretched exponential function was drastically influenced by thermal annealing conditions. It was found that a change of amorphous structures in the linear and lightly branched PET glasses due to annealing resulted in significant acceleration of the rate of volume relaxation. Furthermore, the correlation between the local rearrangement of amorphous network chains and the volume relaxation process of polymer glasses was discussed.
2001-09-01