Surface-enhanced Raman scattering (SERS) was used to study the photodegradation of 3,3-diphenylnaphtho[2,1-b]pyran in acetonitrile solution. The SERS spectra obtained from long UV irradiation of photochromic solutions were compared to those of synthetic reference compounds expected in the degradation process. In order to assist the analysis of spectra, a qualitative assignment of the main SERS lines appearing during the time course of the degradation experiments was performed which allowed us to distinguish the specific spectral contributions of the different photoproducts. We were therefore able to draw hypotheses concerning the major fragments issued from the photodegradation process and to discuss the possible mechanisms for their formation.