Measurements of the Optical Anisotropy of Trapped Molecules in Oriented Polymer Films by Waveguide Raman Spectroscopy (WRS)

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Abstract
The orientation of small molecules trapped in a polymer matrix has been studied by Raman spectroscopy using integrated optical techniques. Results indicate that the orientation of the trapped molecules occurs during mechanical processing of the polymer film and may contribute artifacts to the observed birefringence since solvent molecules are often trapped and oriented during preparation. When the guest molecule was naphthalene, the disappearance of crystal field splitting in the Raman spectrum suggested that an interruption of the intermolecular forces had occurred upon embedding the molecule in a polystyrene matrix. The ability to orient isolated naphthalene molecules indicates that this technique is ideal for studying oriented molecules in a polymer film in the absence of crystal field interactions.