Whitepaper: Raman Spectroscopy for Polymer Analysis

Find out how recent advances in technology have made Raman spectroscopy better and more affordable for polymer analysis than traditional IR spectroscopy…

Vibrational spectroscopy has been used for years for polymer analysis. Traditionally the preferred technique has been infrared (IR) spectroscopy; however, recent advances in technology have made Raman spectroscopy, with its inherent advantages, easier and more affordable than in the past.

Raman and IR spectroscopy differ fundamentally in their mechanisms for detecting vibrations. IR spectroscopy detects vibrations that generate a change in the molecule’s dipole moment. Raman spectroscopy detects vibrations that generate a change in the molecule’s polarisability. Some vibrations can be accompanied by changes in both dipole moment and polarizability; these vibrations are detected by both IR and Raman spectroscopy. In long polymer chains, vibrations of the backbone generally do not induce changes in the dipole moment because adjacent dipoles are cancelled out by repeating units, but the change in polarisability is usually high. This makes Raman spectroscopy particularly useful because it is highly sensitive to the structure and conformation of the polymer backbone. In contrast, IR can be useful for analysing side chains, so the two techniques can be used complementarily…