Temperature-dependent infrared refractive index of polymers from a calibrated attenuated total reflection infrared measurement

Date

2022

Authors

Azam, Md S.
Ranson, Malcolm D.
Hore, Dennis K.

Journal Title

Journal ISSN

Volume Title

Publisher

Applied Spectroscopy

Abstract

We demonstrate a straightforward method by which a commonly available reference sample such as water can be used to calibrate an attenuated total internal reflection infrared absorbance measurement in order to account for the polarization of the beam incident on the internal reflecting element, and the spread of angles about the nominal angle of incidence. This enables quantitative comparison of attenuated total reflection-derived absorbance data with spectra calculated from optical constants. We then apply this calibration to the measurement of temperature-dependent absorption spectra of a polydimethylsiloxane sample. We illustrate that the extracted optical constants scale with the temperature-dependent changes in the polymer density better than the raw absorbance values on vibrational resonance.

Description

Keywords

Attenuated total reflection infrared spectroscopy, ATR-IR, polarization, susceptibility, complex refractive index, temperature-dependence, polymers

Citation

Azam, M. S., Ranson, M. D., & Hore, D. K. (2022). “Temperature-dependent infrared refractive index of polymers from a calibrated attenuated total reflection infrared measurement.” Applied Spectroscopy, 76(10), 1254-1262. https://doi.org/10.1177/00037028221094598