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Methacrylate‐tethered Analogs of the Laser Dye PM567—Synthesis, Copolymerization with Methyl Methacrylate and Photostability of the Copolymers ¶
Author(s) -
AmatGuerri Francisco,
Liras Marta,
Carrascoso María Luisa,
Sastre Roberto
Publication year - 2003
Publication title -
photochemistry and photobiology
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.818
H-Index - 131
eISSN - 1751-1097
pISSN - 0031-8655
DOI - 10.1562/0031-8655(2003)0770577maotld2.0.co2
Subject(s) - copolymer , methacrylate , methyl methacrylate , polymer chemistry , chemistry , photochemistry , materials science , organic chemistry , polymer
The synthesis and characterization of new analogs of the laser dye PM567 (4,4‐difluoro‐1,3,5,7,8‐pentamethyl‐2,6‐diethyl‐4‐bora‐3a,4a‐diaza‐ s ‐indacene) with the 8‐position substituted by a linear chain with n methylenes (n = 1, 3, 5, 10 or 15) tethered with an acetoxy or methacryloyloxy group (PnAc and PnMA, respectively) is described. The monomeric dyes PnMA have been successfully copolymerized with methyl methacrylate (MMA), yielding linear copolymers of high optical quality where the covalently bonded chromophore is separated from the polymeric main chain by a spacer of variable length. The photostability of the solid polymeric materials under UV (310 nm) irradiation (method ASTM G 53‐77) has been compared with those of the model dyes PnAc and PM567 as solid solutions in poly‐MMA (PnAc–PMMA and PM567–PMMA, respectively). In all the cases, the chromophore bound to the polymer is more photostable than that simply dissolved in the same polymer, with photodegradation quantum yields in the range 2.3 × 10 −5 to 4.8 × 10 −5 , which was interpreted as due to additional modes for the dissipation of the absorbed energy along the polymeric chain. In both polymer solutions and copolymers, the length of the polymethylene chain has low or null influence on the photostability. In ethanol solution, PnAc model dyes with polymethylene chains with three or more methylene groups show about the same photostability; this is of an order of magnitude higher than that of the parent dyes P1Ac and PM567 in the same solvent.