Synthesis, Fluorescence and Photoisomerization Studies of Azobenzene-Functionalized Poly(alkyl aryl ether) Dendrimers

A series of azobenzene‐functionalized poly(alkyl aryl ether) dendrimers have been synthesized and their photochemical and photophysical properties in solution and as thin films have been investigated. Although the photochemical behavior of the azodendrimers in solution indicated that the azobenzene units behave independently, very similar to the constituent monomer azobenzene unit, the properties of thin solid films of the dendrimers were distinctly different. The azodendrimers, AzoG1, AzoG2, and AzoG3 were observed to form stable supercooled glasses, which showed long‐wavelength absorption and red emission characteristics of J‐aggregates of the azobenzene chromophores. Reversible photoinduced isomerization of the azodendrimers in the glassy state is described. Strong fluorescence in the red region, attributable directly to the formation of J‐aggregates, is exhibited by azobenzene‐functionalized poly(alkyl aryl ether) dendrimers (see picture), which form stable glasses at room temperature. The reversible photoisomerization of the azodendrimers in their glassy state and in the solution phase are discussed.