Raman Scattering of Synthetic Polymers‐A Review

Abstract

Four years after Raman discovered the Raman effect, the first spectrum of a high polymer, i.e., polystyrene, was observed by Signer and Weiler 111, so the field of Raman spectroscopy of polymers is not a new field. However, it was not until twenty years later that the second Raman spectrum of a polymer, that of poly(methy1 methacrylate), was observed [2]. The reasons for this lack of activity rest on the fact that the sample had to be clear, transparent, and nonfluorescing to obtain a Raman spectrum. Most polymers do not fall in any of these categories. Workers like Nielsen [3,4] (PE and PTFE), Tobin [5,6] (PE, PP, PTFE), Brown [7] (PE), and Tadokoro [8,9] (POM, PEG) obtained spectra with Toronto arc spectrometers out only after an enormous amount of diligent effort. However, these workers were successful in drawing attention to the potential of Raman spectroscopy as a tool for the characterization of polymers. Nielsen's review [lo] presented substantial motivation for work in this area, but the experimental difficulties tended to discourage everyone. With the advent of laser excitation and the high quality of the first reported [ll] laser Raman spectrum of a polymer, a revival of work and interest in this field ensued and many workers are now active in the field, as reflected by the increasing number of papers in Raman spectroscopy of polymers. One review of laserexcited Raman spectroscopy of polymers has already beenwritten [12].