Liquid (viscous) macromonomer was analyzed in transmission mode, after pouring samples between NaCl plates. Spectra of films after photocuring and lyophilized PEGylated fibrinogen were obtained using reflection mode and the ATR snap-in with diamond crystal. Spectra were analyzed using EZ OMNIC software. Two-dimensional correlation spectroscopy (2D-COS) was used to obtain the sequence of individual spectral changes that resulted after the degradation.