A review, with .apprx.121 refs., on use of FTIR polarization spectroscopy methods in studies of motion of chain segments, including side chains of LCPs under external perturbation. Studies include structure-dependent alignment of side-chain LC polyacrylates on anisotropic surfaces; elec. field-induced orientation and relaxation of a liq. crystal, a side-chain LCP, and a LC guest-host system; reorientation dynamics of a ferroelec. side-chain LCP in a polarity-switched elec. field; alignment of side-chain LC polyesters under laser irradn.; shear-induced orientation of chiral smectic LC polysiloxanes; and orientation mechanism of a liq. single crystal elastomer during cyclic deformation and recovery are studied. Theor. principles and instrumentation for FTIR polarization spectroscopy are described.