Substituent-dependence of the third-order nonlinear optical properties of 2, 5-dialkoxy-PPV derivatives

摘要

The influence of the chemical structure on the X~(3) of organic molecules has been selectively investigated in three poly (2, 5-dialkoxy-1, 4-phenylenevinylene) polymers. They have similar degrees of polymerization and polydispersity indexes and differ only for the structure of the side groups in the 2, 5 positions of the phenylene rings, that are respectively C8 linear and substituted-PPVs exhibit a small Ikm X~(3) and a large, negative Re X~(3) at lambda=1064 nm. The obtained results yield evide3nce of a considerable dependence of the thrid-order nonlinear optical properties on the steric effect of the substituents.