Orientational relaxation of three different dendrimers in polycarbonate matrix investigated by optical poling

摘要

We report on all-optical poling relaxation of E-O active dendrimers photo-patterned in the polycarbonate matrix. Three kinds of polyester type dendrimers G0, G1 and G2 containing azobenzene in the core were used as second-order nonlinear optical active chromophores to create noncentrosymmetry inside the material. We used a guest-host type system of these structures spin-coated on a glass substrate. These samples were poled by using an all-optical poling method, where the polar electric field of electromagnetic waves enables us to orient dendrimer molecules creating a quasi-phase-matched grating of nonlinear second-order susceptibility.(2). Molecular orientation and subsequent dark relaxation kinetics in the samples with different poling beam applied energies were measured. Theoretical modeling of the poling relaxation kinetic revealed a set of characteristic time constants, which were interpreted by different relaxation mechanisms.