Publication
Photochromic hybrid sol-gel films containning naphtopyrans
| Summary: | Several photochromic benzo- and naphthopyrans were embedded in hybrid organic-inorganic ureasilicate based films obtained by a sol-gel process. The resulting films, containing 0,1 % (w/w) of the photochromic compound, were transparent and flexible and for naphthopyrans they were colourless or presented just a slight colouration. Under UV continuous irradiation the films developed a significant absorption in the visible region that fades in the dark with variable kinetics depending on the naphthopyran structure. 2,2-Diphenyl-3H-naphtho[2,1-b]pyran films showed a very fast colouration under UV light giving rise to coloured open forms, containing mainly the TC isomer (98%) along with a very small amount of the more stable TT isomer (2%), that practically returned to the initial absorbance in one minute. |
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| Main Authors: | Coelho, Paulo J. |
| Other Authors: | Carvalho, Luís M.; Gonçalves, Luís F. F. F.; Silva, Carlos J. R.; Campos, Ana M. F. Oliveira; Gomes, M. J. M. |
| Subject: | Naphtopyran Sol-gel Ureasilicate Organic-inorganic hybrid Phtochromism UV light Kinetics Naphthopyran Photochromism |
| Year: | 2010 |
| Country: | Portugal |
| Document type: | article |
| Access type: | restricted access |
| Associated institution: | Universidade do Minho |
| Language: | English |
| Origin: | RepositóriUM - Universidade do Minho |
| Summary: | Several photochromic benzo- and naphthopyrans were embedded in hybrid organic-inorganic ureasilicate based films obtained by a sol-gel process. The resulting films, containing 0,1 % (w/w) of the photochromic compound, were transparent and flexible and for naphthopyrans they were colourless or presented just a slight colouration. Under UV continuous irradiation the films developed a significant absorption in the visible region that fades in the dark with variable kinetics depending on the naphthopyran structure. 2,2-Diphenyl-3H-naphtho[2,1-b]pyran films showed a very fast colouration under UV light giving rise to coloured open forms, containing mainly the TC isomer (98%) along with a very small amount of the more stable TT isomer (2%), that practically returned to the initial absorbance in one minute. |
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