Fourier Transform Infrared (FTIR) Spectroscopy
FTIR analysis provides spectral information that is essentially a molecular fingerprint for organic, polymeric, and in some case inorganic materials. This technique is extremely useful for identifying base polymer compositions and organic contaminants. The FTIR spectrum of the unknown material can be compared for "best matches" with libraries of spectra that have been cataloged for known materials.
This paper discusses FTIR analysis in more detail:
A complete listing of all the papers on this site can be found here.