We report a large electrostrictive strain in electron irradiated poly(vinylidene fluoride–trifluoroethylene) copolymer at a composition with 65 mol &percent; vinylidene fluoride, which also exhibits a large ratio of strain to applied field (∼275 pm/V). The strain response is nearly independent of the external driving condition (unipolar or bipolar field) and does not change with temperature in about 20 °C temperature range near room temperature. Moreover, near room temperature, the material can reach a relatively high quasistatic longitudinal electromechanical coupling factork33∼0.33.©1998 American Institute of Physics.