CALCULATION OF THE VIBRATIONAL-SPECTRA OF MACROMOLECULES DURING DEFORMATION OF A POLYMER

The variation of band intensities in the IR and Raman spectra of a pol ymer during its deformation was calculated for polyethylene terephthal ate. The dependence of the band intensity on the applied force is nonl inear and is determined by orientation of the vector of the dipole mom ent derivative of a molecule with respect to the natural coordinate me asured relative to the axis of rotation. For bands of backbone vibrati ons with parallel dichroism, the contribution due to a change in the o rientation of the vector of the derivative of the dipole moment depend s on the degree of deformation, while bands with perpendicular dichroi sm exhibit no such dependence and are less sensitive to deformation-in duced changes in chain conformation.