The orientation behavior of a segmented poly(tetramethylene oxide) (PTMO) zwitterionomer, with a narrow polydispersity PTMO segmental molecular weight of 5.2 x 10(3), a melting point of 17 degreesC, and elastomeric characteristics, was studied using infrared linear dichroism. The results obtained show that when the amorphous zwitterionomer is stretched at ambient temperature, the PTMO chains orient in the stretch direction. At a draw ratio of approximately 3, strain-induced crystallization occurs and increases with strain amplitude. The chain axis of the crystallized PTMO segments are almost perfectly oriented in the stretch direction, whereas the orientation of the amorphous segments is low and undergoes no further changes during crystallization. The degree of crystallization was also determined from the spectra (22% for a draw ratio of 5.6). The crystallization kinetics were shown to follow the Avrami equation, indicating one-dimensional growth (n = 0.8). Orientation relaxation following deformation was also studied as a function of temperature at draw ratios and temperatures where strain-induced crystallization is avoided. Little orientation was detected in the ionic regions of the polymer during stretching. The orientation function for the PTMO soft blocks decreases, and the relaxation rate increases with increasing temperature. Time-temperature superposition of the relaxation curves is discussed in relation to the hard (or cluster) phase transition.