The photochromic organic molecule 2,3-diphenyl indenone oxide (DPIO) has been incorporated into transparent silica gel-PMMA nanocomposites. Under ultraviolet illumination, the colorless DPIO molecule transforms into 1,3-diphenyl-2-benzo-pyrillium-4- oxide (DPBO), which is deep red. Upon exposure to visible light, DPBO transforms reversibly into DPIO. Some DPBO, however, irreversibly decomposes into 3,4-diphenyl isocoumarin (DPIC) and other by-products. In this preliminary study, the rate of photochromic fatigue for a variety of samples of DPIO-doped PMMA, silica gel-PMMA nanocomposites, and ORMOSILs is presented and discussed. The prospects for DPIO-based photochromic materials exhibiting long-term stability are discussed.