Abstract
Three complementary approaches to the construction of electric field polable high-Tg (glass transition temperature) polyimides and polyureas as second-order NLO materials are discussed. In the first approach, copolymerization of bismaleimides with o,o'- diallylbisphenol A followed by functionalization with high-(beta) NLO chromophores using a Mitsunobu procedure yields, after poling and curing, a series of heavily crosslinked chromophoric polyimides with Tg values as high as approximately 260 degree(s)C and (chi) <SUP>(2</SUP>) responses as high as 1.0 X 10<SUP>-7</SUP> esu (42 pm/V at (lambda) <SUB>o</SUB> equals 1064 nm, 1.17 eV). In the second two approaches, copolymerization of the chromophore 4,5-bis(4'aminophenyl)-2-(4'-nitrophenyl)imidazole with bismaleimides or diisocyanates yields polyimides and polyureas with Tg values as high as 292 degree(s)C and partially resonant (chi) <SUP>(2</SUP>) values as high as 0.62 X 10<SUP>-7</SUP> esu (25 pm/V at (lambda) <SUB>o</SUB> equals 1064 nm). It is found that careful attention to the details of curing and crosslinking during poling results in NLO-active matrices exhibiting negligible decay in (chi) <SUP>(2</SUP>) on aging in air at 100 degree(s)C for periods of 1000 - 4000 h. The imidazole- based materials exhibit only approximately 10% (chi) <SUP>(2</SUP>) decay on aging for 100 h at 200 degree(s)C under N<SUB>2</SUB>.
Published Version
Talk to us
Join us for a 30 min session where you can share your feedback and ask us any queries you have
Schedule a call