PERFORMANCE AND MECHANISMS OF HINDERED AMINE LIGHT STABILIZER IN SPIROOXAZINE PHOTOSTABILIZATION

One of the key requirements for optical switching apertures for ophtal mic, building and automobile glazing is long lived product. However, o xidation of a spirooxazine yields photoproducts such as oxindole deriv atives, naphthoxazole, dihydro-2,6-quinolone and 1-N-formylimino-2-nap hthoquinone devoid of photochromic activity, and limits the commercial isation of these useful systems. Achieving this long lived product can be provide by use of hindered amine light stabilizers (HALS). This pa per describs the comportment of a spirooxazine irradiated in the prese nce of a HALS and the main stabilization mechanisms are discussed.