The electromechanical properties of a segmented polyurethane elastomer were investigated as functions of temperature and frequency. Two transitional phenomena were observed in the temperature range from -50 to 85 degrees C. In these transition regions, the electric field induced strain coefficient exhibits large increases, which indicate that the effect of the transition processes is significant. The experimental analysis suggests that the transitional processes in the polyurethane are related to the chain-segment motions. From the elastic compliance and the dielectric constant data, the contribution of the uniform Maxwell stress was determined. It was found that the contribution of the Maxwell stress effect to the measured strain coefficient increased from about 10% below the glass transition temperature (T-g) (similar to -25 degrees C) to about 50 and 35% for the frequencies of 10 and 100 Hz, respectively, at similar to 40 degrees C, which is above T-g. The large difference between the measured strain response and the calculated Maxwell stress effect indicates a significant contribution to the field-induced strain from other mechanisms, such as electrostriction.