The post-polymerization modification of porous glycidyl methacrylate – ethylene glycol dimethacrylate microspheres was subsequently achieved firstly by reacting the glycidyl functionalities with sodium cyclopentadienide and secondly by the Diels-Alder click reaction with maleic anhydride. Analysis of the surface-decorated spherical polymeric materials was performed using the Fourier transform vibrational (Raman), and infrared (attenuated total reflectance) spectroscopies. In addition, the FT-IR photoacoustic spectroscopy as an alternative, and interesting tool in the chemical analysis of modified polymers was used. The results from those three non-destructive complementary spectroscopic methods providing important molecular structural information were compared together.