Photoreactions in viscous media

H. Mauser, The evolution of complicated photoreactions in viscous media, Z. Naturforschg. 34c(1979)1264. 

In Section 3.4 in eqs. (3.101)-(3.123) the relationships for photoreactions taking place in viscous media have been derived and examples of reaction types are given. Furthermore this special problem of unstirred solution is treated in the literature [205,206]. In the following these equations are used to determine the parameters of the photoisomerisation of azobenzene in a polysiloxane block of distyrylpyrazine in a microcystalline layer, and to observe the photoreaction of a fulgide liquid crystal adherent to a polymeric backbone. As a flrst approximation the problem of diffusion is excluded. 

Most integrals cannot be solved in a closed form because of the time dependence of the photokinetic factor (except at specific reaction conditions). Therefore the integrals have to be solved numerically. When the solution cannot be homogenised during the photoreaction by stirring (viscous media) dependencies on time and position have to be taken into account. 

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