This spectral region was thus chosen for data processing. This
operation consists in a set of spectral treatments. First, the CH region
was extracted (Raman spectra were cut between 2730 and 3185cm−1
and IR spectra between 2730 and 3135cm−1), and a linear baseline
was subtracted. The second important step was the spectra normal-
ization. Indeed, all the analyzed materials were not of the same size or
thickness and in order toget rid of this analytical parameter, the cut
spectra were all scaled to the same intensity. Then, a more thorough
step consisting in a spectral decomposition of the CH stretching region
using home-made software was established. The decomposition
procedure was first defined according to several parameters: the
number of bands and their position (P), the area (A), the full width
at half maximum (W) and the profile (K) of each decomposition band
(Gaussian/Lorentzian).