A Simple Method for Obtaining the Information of Orientation Distribution Using Polarized Raman Spectroscopy: Orientation Study of Structural Units in Poly(lactic acid)

Abstract

A simple approach using polarized Raman spectroscopy has been employed to study the molecular orientation distribution in both the crystalline and amorphous regions of uniaxially oriented poly(l-lactic acid) (PLLA) films. The effect of morphology on the intensity of the Raman bands was evaluated to provide qualitative information on the distributions of the crystalline and amorphous regions to the peak intensities. The angular dependence of the scattered intensity of assignable vibration bands was analyzed to quantify the orientation degree of the symmetry axis of Raman tensors. The results showed that the measurement of polarization of scattered intensity as a function of rotating angle can provide semiqualitative information on the shape of the orientation distribution function. On the basis of the results, orientational variation of both amorphous and crystalline chains can be described under the deformation of film and compared with previous studies.