Polymeric siloxanes with a substituent and the spirobenzopyran moiety: Effect of polar substituent on the photochromic properties

✍ Scribed by Ren Nakao; Norikazu Ueda; Yasuo Abe; Toyokazu Horii; Hiroo Inoue

• Publisher: John Wiley and Sons
• Year: 1996
• Tongue: English
• Weight: 314 KB
• Volume: 7
• Category: Article
• ISSN: 1042-7147
• DOI: 10.1002/(sici)1099-1581(199611)7:11<863::aid-pat597>3.0.co;2-t

✦ Synopsis

Oligomeric polysiloxanes having the spirobenzopyran moiety and various substituents were prepared. The polymers were photochromic; the color changed from colorless to red on U V irradiation and the color faded on visible irradiation or on standing in the dark. The thermal decoloration was depressed by the polar substituents. However, the effect of the bulky substituent, which had been observed in the rigid siloxane resins, was not detected. In the inorganiclorganic hybrid siloxane gels, the silica/(spirobenzopyran-bonding polysiloxane) system and the (spirobenzopyran-bonding si1ica)lpolysiloxane system, the thermal decoloration was also affected by the polar substituent introduced into the polysiloxane portion. The effect was larger in the first case than in the second. The result can be interpreted by the term of the preferential diffusion of polar spirobenzopyran to the vicinity of the polar substituents during the gelation.