Infrared Spectroscopy of Glasses

Infrared (IR) and Raman are two complementary techniques of vibrational spectroscopy both of which have been used extensively over the years in glass studies. This chapter introduces infrared spectroscopy and its potential in glass studies with emphasis on glasses in bulk and thin film forms. It commences with a brief review of the basics on refractive index and dielectric function that allow defining the optical and dielectric properties measured in the infrared. Then, the chapter outlines the main methods used to treat reflectivity data measured on bulk materials which absorb strongly in the infrared, and give the formalism to treat spectra of thin films. Key aspects of the Fourier-transform infrared (FT-IR) instrumentation are presented, and the procedure of measuring infrared spectra is outlined using as example the reflectance spectrum of silica glass. The chapter concludes by summarizing key points of glass studies by infrared spectroscopy.