Using secondary derivative spectroscopy and Fourier self-deconvolution techniques

the resolution of overlapping different carbonyl stretching components has been enhanced and a new carbonyl stretching componont at 1715 cm-1 has been found. Spectra subtraction and curve fitting have been used to follow the changes in intensity of these three components in Amide I region of polyurethanes during thermal treatments. The change in intensity of the newly found 1715 cm-1 component as a result of thermal treatment is quite similar to the be-havior of the free carbonyl stretching component (1730cm-1) and generally opposite in be-havior to the strongly hydrogen bonded one (1702-1705cm-1) and therefore

can be assig-ned to dissordered interphase region.