We have measured by micro‐Raman spectroscopy the surface enhanced Raman scattering (SERS) spectra of about 2 monolayers of C70on Ag surface. New Raman bands of the fullerene molecule have been found. The time evolution (from C70to amorphous carbon) of the SERS spectra, under high laser power density illumination in air, provides evidence of photochemical reactions. New bands in the Raman spectra appearing with the time have been attributed to intermediate products of these photochemical reactions. ©1995 American Institute of Physics.