SYNTHESIS AND NONLINEAR-OPTICAL PROPERTIES OF END-GROUP MODIFIED AROMATIC ESTERS AS CHAINED CHROMOPHORES

We synthesized aromatic ester derivatives with some electron accepting groups at molecular ends as new class of nonlinear optical (NLO) acti ve chromophores (ArESn-X, n = 2, 3, X = CN, CF3, NO2 DCV). Some second -order NLO properties for poled polymer films consisting of poly(methy l methacrylate) (PMMA) doped with 10 wt.-% ArESn-X (ArESn-X/PMMA) were investigated. UV/vis spectra of these polymer films have cutoff wavel engths (lambda(co)) of about 300 similar to 380 nm, which are much sho rter than in the case of p-nitroaniline (pNA) (lambda(co) = ca. 450 nm ) as a typical strong donor-acceptor (D-A) molecule. In addition, some of these polymer films exhibited larger second-order nonlinear coeffi cient (d(33)) values than PMMA film doped with 10 wt.-% pNA (pNA/PMMA) (2.8 x 10(-9) esu). Namely, ArES3-CN (d(33) = 3.1 X 10(-9) esu, 10 wt .-% in PMMA), ArES3-NO2 (3.0 x 10(-9) esu, 10 wt.-% in PMMA) and ArES2 -DCV (4.0 x 10(-9) esu, 10 wt.-% in PMMA) showed not only excellent se cond-order MLO activity but also excellent transparency in the visible region (lambda(co) = 304 nm (ArES3-CN), 340 nm (ArES3-NO2) and 370 nm (ArES2-DCV), respectively). Consequently, these compounds are believe d to be promising chromophores for second-order nonlinear optics.