Vibrational spectral study of molecular orientation in vitreous fibers

Preferential orientation of polymeric chains with respect to the principle axis in completely noncrystalline, vitreous fibers is demonstrated by laser Raman and infrared reflectance study of sodium metaphosphate glass fibers. The polarization dependence of Raman intensities in 24 scattering arrangements have been obtained by varying the incident and scattered radiation propagation and polarization directions and are compared to calculated Raman intensity ratios for uniaxial orientation of the chains. Infrared dichroic ratio data were obtained from a Kramers-Kronig transformation analysis of polarized reflection spectra on oriented fibers, and employed to compute the averages of the angles the metaphosphate chains make with the fiber axis.