EFFECT OF MOLECULAR-ORIENTATION IN MATRIX ON THE PHOTOCHROMISM OF 9' SUBSTITUTED SPIRONAPHTHOXAZINES

As photochromic agents, 1,3,3-trimethylspiro (indoline-2,3' [3 H] naph tho [2,1-b] [1,4] oxazine) (TM-SNO) and its 9'-substituted spironaphth oxazine derivatives were doped in poly(methyl methacrylate) (PMMA) fil ms by solution casting. Effect of molecular orientation of PMMA films stretched at various ratios on the color decay kinetics of the photoch romic agents after UV irradiation was investigated. Colorless PMMA fil ms containing the spironaphthoxazines developed a blue color having an absorption maximum at about 600 nm, after UV irradiation with a 100 W high pressure mercury lamp for 60s. In the dark at room temperature, the color decay of 9'-hexafluoropropene substituted spironaphthoxazine (TM-Rf-SNO) proceeded slower than the others. However, the reciprocal of the absorbance at the peak was proportional to time, in all of the color decay processes. The color decay rate was evaluated by the slop e (k) as a parameter. The k value increased with increasing stretch ra tio in different types of stretching. These results were interpreted i n terms of polymer entanglement by stretching.