In this work, alternating poly(butyl vinyl ether-co-acrylonitrile) (P(BVE-co-AN)) copolymer was found to exhibit temperature-dependent strain recovery when it was heated through its glass-transition temperature (Tg ~ 26 °C). This copolymer is amorphous and contains polar side groups in its structure, thereby exhibiting a switch in permittivity when passing through the glass transition. The strain-recovery effect accompanied by the change in permittivity and thickness occurring around room temperature can be exploited in electro-active applications such as thermal capacitive sensors and energy harvesting