Laser Flash Photolysis in High-Speed Photopolymer Coating Layers
The sensitization mechanisms of two systems of ketocoumarin dyes with a radical-generating reagent (10,10′-carbonylbis[1,1,7,7-tetramethyl-2,3,6,7-tetrahydro-1H,5H,11H-[1]benzopyrano [6,7,8-ij]quinolizin-11-one] (KCD-J), 3,3′-carbonylbis]7-(diethylamino)coumarin] (KCD-DA) with 3,3′,4,4′-tetrakis(t-b...
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Published in | Bulletin of the Chemical Society of Japan Vol. 68; no. 6; pp. 1661 - 1668 |
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Main Authors | , , , , , , |
Format | Journal Article |
Language | English |
Published |
Tokyo
The Chemical Society of Japan
01.06.1995
Chemical Society of Japan |
Online Access | Get full text |
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Summary: | The sensitization mechanisms of two systems of ketocoumarin dyes with a radical-generating reagent (10,10′-carbonylbis[1,1,7,7-tetramethyl-2,3,6,7-tetrahydro-1H,5H,11H-[1]benzopyrano [6,7,8-ij]quinolizin-11-one] (KCD-J), 3,3′-carbonylbis]7-(diethylamino)coumarin] (KCD-DA) with 3,3′,4,4′-tetrakis(t-butyldioxycarbonyl)benzophenone (I) in poly(methylmethacrylate) film) and of two systems of coumarin dyes (10-(2-benzothiazolyl)-1,1,7,7-tetramethyl-2,3,6,7-tetrahydro-1H,5H,11H-[1]benzopyrano[6,7,8-ij]quinolizin-11-one (CD-J), 3-(2-benzothiazolyl)-7-(diethylamino)coumarin (CD-DA) with I in the film) have been investigated by laser flash photolysis using a total-reflection cell. The fluorescence of the dyes was efficiently quenched by I with static quenching distances of 8.1, 8.6, 15.0, and 10.9 Å for KCD-J, KCD-DA, CD-J, and CD-DA. The decay time of the triplet was moderately quenched by I with a quenching rate (kq) of 5.8 × 105 mol−1 dm3 s−1 for KCD-DA, and slightly with a kq of less than 1 × 105 mol−1 dm3 s−1 for KCD-J; none of the triplet was detected on CD-J and CD-DA. These results suggested that a static sensitization from the fluorescent-excited dyes to I is predominant in photoinitiation systems. |
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ISSN: | 0009-2673 1348-0634 |
DOI: | 10.1246/bcsj.68.1661 |