Synthesis of third-order nonlinear optical polyacrylates containing an azobenzene side chain via atom transfer radical polymerization

A series of polyacrylates containing different substituted-azobenzene chromophores were synthesized and polymerized via atom transfer radical polymerization. Nonlinear optical homopolymers containing an azobenzene side chain, of controllable molecular mass and low polydispersity (1.1–1.4) were obtained. In addition, side-chain copolymers were prepared in which the composition of the copolymers was controlled by using different feed ratios of the azobenzene monomer and methyl methacrylate. The third-order nonlinear optical properties of azobenzene monomers and their polymers were measured using the degenerated four-wave mixing technique. Each of the polymers displayed a high χ(3) of about 10−11 esu and rapid response time in femto-second magnitude. The effect of substituents on the azobenzene group and the composition of the polymer chain on the third-order nonlinear optical properties of the polymers were investigated.