Photochromic properties of 1,3,3-trimethylspiro[indoline-2,3′-[3H]naphtho[2,1-b][1,4]oxazine] doped in PMMA and epoxy resin thin films

Irradiation of colorless 1,3,3-trimethylspiro[indoline-2,3′-[3H]naphtho[2,1-b][1,4]oxazine] SO doped in PMMA and epoxy resin with UV light (at 366 nm) results in the formation of an intensely colored zwitterionic photomerocyanine PMC. The reverse reaction was photochemically induced by irradiation with white light. Photocoloration and photobleaching reactions follow a first-order rate equation. It was found that photocoloration rate constant of SO in PMMA film is greater than that in epoxy resin. On the other hand, the photobleaching rate constant is almost identical in both matrices. Spirooxazine doped in epoxy resin shows much better fatigue resistance than that doped in PMMA.