Polarization measurements in macro- and micro-Raman spectroscopies: Molecular orientations in thin films and azo-dye containing polymer systems

A thorough understanding of the interaction mechanisms between the polarized beams and a measurement of the energy exchanges in absorption-reflection or in scattering processes are critical to carry out spectroscopic studies. This review covers some basic knowledge, concepts, and experimental cautions to keep in mind in order to perform precise macro- and micro-Raman polarized experiments and accomplish the related data treatments. The most probable orientational molecular distribution functions and their construction from polarized Raman data obtained in thin films of macromolecular materials possessing either uniaxial or biaxial symmetry properties are outlined. As illustrative examples, some results of various molecular systems and azo-dye containing polymer films are discussed.