The photochemistry of condensed films of OClO was examined with photofragment spectroscopy. Photolysis of multilayers of OCIO on a polycrystalline Pt surface with 355 nm light yields predominantly atomic O, O2, atomic Cl, and ClO photofragments. We have measured the quantum yield for the Cl product channel to be 0.8¿0.1, which is approximately 800 times higher than reported values for the non-resonant gas-phase photolysis of OClO. This result may have implications for stratospheric ozone chemistry. ¿ American Geophysical Union 1996