Synthesis and nonlinear optical properties of aromatic esters with an electron donor and an electron acceptor end group

Abstract

We synthesized a series of aromatic esters having an electron donating and an electron accepting end group as a new class of nonlinear optical (NLO) active chromophores (ArESn D-A, n = 2,3, D = MeO (as reference), MeS and Me2N, A = CN). Second-order NLO properties for poled polymer films consisting of poly(methyl methacrylate) (PMMA) doped with 10 wt.-% ArESn D-A (ArESn D-A/PMMA) were investigated. The UV/vis spectra of these polymer films have cutoff wavelengths (λco) of about 350 ˜ 370 nm, which are much shorter than in the case of p-nitroaniline (pNA) (λco = 473 nm) which is a typical strong donor-acceptor (D-π-A) molecule. In addition, some of these polymer films exhibit higher second-order nonlinear coefficients (d33) than a PMMA film doped with 10 wt.-% pNA (pNA/PMMA) (2.8×10–9 esu). Namely, ArES3 Me2N-CN (d33 = 5.6×10–9 esu, 10 wt.-% in PMMA) and ArES2 Me2N-CN (3.8×10–9 esu, 10 wt.-% in PMMA) showed excellent second-order NLO activity as well as transparency in the visible region (λco: 362 nm for ArES3 Me2N-CN and 366 nm for ArES2 Me2N-CN, respectively).