Spectroscopic investigation of organosilicon polymers. I. Vibrational analysis of poly(tetramethyl‐p‐silphenylene‐siloxane)

Abstract

This article is a detailed, normal coordinate analysis of an isolated chain of poly(tetramethyl‐p‐silphenylene‐siloxane), based on results obtained for the corresponding monomer and a recent x‐ray structure. Predicted vibrational frequencies are compared with new experimental infrared (IR) and Raman data obtained from powder and well oriented films. Vibrational spectra were also obtained for a deuterio derivative in which all hydrogens in the benzene rings were replaced with deuterium atoms. The results indicate that an intermode mixing occurs between vibrations of the ring and the saturated part which lead to low frequency normal modes characteristic of the chain. The simplified valence force field obtained for this polymer should provide a useful tool for understanding the vibrational spectra of other members of the class of polysiloxanes.