This procedure can be used for a variety of applications, including identifying unlabeled material, process control, raw material acceptance, product evaluation, and compositional change during environmental testing.

Rubber chemicals vary widely in their chemical and physical properties. Infrared spectrophotometers vary in the presentation of a spectrum (some are linear with absorbance, others with transmittance, some use grating for energy dispersion, others use a sodium chloride prism, some obtain a spectrum through a mathematical Fourier Transform, and the like). For these reasons, a single universal method of specimen preparation and set of instrument parameters is not possible.

By using a specific sampling procedure and operating conditions, a given spectrophotometer will give an absorption curve that is characteristic of the rubber chemical or mixture under investigation.

The ability to superimpose the infrared spectrum of the test specimen upon that of a reference specimen, obtained under the same conditions, is evidence that the two are identical.

The presence of additional absorption bands in either the test specimen or the reference specimen indicates the presence of one or more additional components.