title: Fast decoloration of spironaphthooxazine bound to a poly(dimethylsiloxane) network.
abstract: Spironaphthooxazine (SNO) was attached to a three-dimensional network of polysiloxane through the allyloxy group on C-7 of the naphthalene ring of SNO, and the photochemical coloration and thermal decoloration behaviors of this material (Film-P) were examined by comparing their properties with those of model SNO having a 7-propyloxynaphthyl group in solution, in a doped polysiloxane film (Film-D), and in a doped PMMA film. For Film-P, the SNO units were connected to a part of the vinyl groups on the Si atoms of a linear polysiloxane by hydrosilylation, and the remaining vinyl groups were bridged by the bifunctional linear polysiloxane possessing two hydrosilyl groups at both ends of the chain. While Film-P containing 1.7 x 10(-3) mol dm(-3) of the SNO unit formed a transparent film, Film-D containing more than 1.2 x 10(-3) mol dm(-3) could not form a transparent film but segregation of SNO occurred. A transparent Film-D was prepared at 0.54 x 10(-3) mol dm(-3) SNO concentration. The decoloration reaction rate of Film-D was faster than those for Film-P, solutions, and PMMA. However, due to the low concentration, the coloration of Film-D was weak. When the concentration of SNO in Film-P was increased 5.7 times, the decoloration rate became 3.6 times faster. Its half-life time was 0.9 s, which is 3.1 times as fast as that of corresponding solution in hexamethyldisiloxane.
authors.affiliation: Department of Advanced Materials Chemistry, Graduate School of Enginieering, Yokohama National University, Yokohama, Japan 240-8501.
authors.forename: Tsuyoshi
authors.initials: T
authors.lastname: Gushiken
authors.forename: Masako
authors.initials: M
authors.lastname: Saito
authors.forename: Takashi
authors.initials: T
authors.lastname: Ubukata
authors.forename: Yasushi
authors.initials: Y
authors.lastname: Yokoyama