Raman spectroscopy was also applied as a complementary technique to infrared spectroscopy. Less commonly used than IR spectroscopy, Raman techniques measure the inelastic scattering of light, depending on the vibrational modes of non-polar bonds of a molecule when excited by an intense monochromatic source as a laser. Raman spectroscopy is proposed with the following aims:
- to determine what kind of information can be obtained;
-to study the variability of the observed features related to the chemical composition;
- to evaluate the discriminating power of the technique;
-to couple analytical information with the one obtained with IR techniques;
- to identify the components of the paints and to draw a chemical profile.