IR SPECTRAL DEPTH PROFILING USING FOURIER-TRANSFORM PHOTOTHERMAL BEAM DEFLECTION

FTIR photothermal beam-deflection spectroscopy (PBDS) was used to make spectral depth-profiling measurements with synthetic bilayer sample of polyethylene/nitrocellulose, with a commercial plastic having surface printing and with a single human hair. A Digilab interferometer modified to operate at several scan speeds was used to record the spectra, without the cell-resonance problems found with photoacoustic spectroscopy (PAS). The utility of spectral depth profiling is discussed; significant S/N improvements seem to be needed and, with either PBDS or PAS, a wider range of modulation frequencies is required for the methods to be useful.