A series of polydimethylsiloxane (PDMS)/polycarbonate (PC) block copolymers with varying compns. were investigated by simultaneous mech. and Fourier transform near-IR (FTNIR) spectroscopic (rheo-optical) measurements to study segmental orientation during elongation-to-break and cyclic elongation-recovery procedures. Depending on the compn. and the block lengths of the copolymers, different orientational and recovery phenomena were obsd. for the hard (PC) and soft (PDMS) segments.