Surface-enhanced Raman scattering (SERS) studies on the photodegradation of 3,3-diphenylnaphtho[2,1-b]pyran in solution

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