Micro-infrared spectroscopy analyses were performed in an
Attenuated Total Reflectance (mono-ATR) mode using a Bruker
Equinox 55 spectrometer coupled to an IRscope II microscope
equipped with a liquid nitrogen-cooled MCT detector. A 20x ATR
objective was used. It is equipped with a Germanium crystal(mono
reflection) working whether in a visual mode for choosing the area to
analyze, or in an IR mode for the measurement. This crystal needs a
contact with the analyzed object, and depending on the material
hardness, it can lead to some damage. 200 scans were accumulated
between 4000 and 600 cm−1 with a 4cm−1 resolution.