Application of a new quantitative optical depth profiling technique for the diffusion of polymers

The concentration profiles of amorphous polystyrene in a polystyrene/polyvinyl methyl ether laminated film after heat treatments have been investigated by a new depth profiling technique using multiple-angle attenuated total reflection Fourier transform infrared (ATR/FT-IR) spectroscopy. An estimated profile or information about the wave form of the profile is not required in order to perform the depth profiling calculation. All angle-dependent spectra are obtained with a nonpolarized incident beam of known degree of polarization. The accuracy of the calculated profiles has been confirmed by comparisons between spectral intensities from experiment and those from exact optical theory at frequencies other than the profiling frequency. The quantitative nature of this technique has been shown via consistent areas under the volume fraction profiles of polystyrene in the laminated him after consecutive heat treatments.