Publication: Thermal cis-to-trans isomerization of triazene dyes in doped polymer films

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Title	Thermal cis-to-trans isomerization of triazene dyes in doped polymer films
Authors/Editors*	R. Tabone, M. Barra
Where published*	Dyes and Pigments
How published*	Journal
Year*	2011
Volume	88
Number
Pages	180-186
Publisher	Elsevier
Keywords	photochromism, triazenes, Z-E isomerization
Link	http://dx.doi.org/10.1016/j.dyepig.2010.06.006
Abstract	The kinetics of the thermal conversion of the cis to the trans isomeric forms of 1,3-diphenyltriazene and 1-phenyltriazenes derived from cyclic amines were determined in poly(methyl methacrylate) and polystyrene doped films in the glassy state, by means of UV-visible absorption spectroscopy. The kinetics of 1,3-diphenyltriazene are very well explained by a two-exponential function, whilst those of 1-phenyltriazene derivates fit a first-order rate law. In all cases, the rate of thermal cis-to-trans isomerization is higher in poly(methyl methacrylate) than in polystyrene films. Rate dependence on dye structure and polymer matrix polarity is consistent with isomerization taking place via a rotation mechanism.