IR spectroscopy allows the identification of different polymers by comparing spectra with databases. Simple material mix-ups can thus be reliably excluded. IR spectroscopy can also be used to characterise the main components of paint systems.
To determine the glass fibre content, the annealing residue of a sample is determined. While organic components burn during annealing, the inorganic glass fibres remain in the crucible. Their proportion can be determined by weighing.
To confirm the correct mixing ratio in a polymer blend (e.g. PC/ABS), additional thermal tests such as measurements of the Vicat softening temperature or the melting point can be used.