Nonlinear optical chromophores with good transparency and high thermal stability

In order to improve the transparency and thermal stabilities of nonlinear o ptical (NLO) chromophores, new materials based on the azo benzene chromopho re having 1,3,5-triazine groups were prepared. Their NLO properties were ex perimentally derived using a two-level model. Compared with corresponding N LO chromophores p-nitroaniline (PNA) and C.I. Disperse Red 1, the newly syn thesised chromophores displayed better transparency and higher thermal stab ility. The reaction of a new NLO chromophore with a dianhydride resulted in polyimide that was converted to a poled polymer which had a d(33) value of 69 pm/v, a T-g of 225 degrees C, decomposition temperature of 354 degrees C and an absorption cut-off below 450 mm, indicating its ability for harmon ic generation application in the blue and green regions. (C) 2000 Elsevier Science Ltd. All rights reserved.