Outstanding Poling Stability of a New Cross-Linked Nonlinear Optical (NLO) Material from a Low Molecular Weight Chromophore

• Published in: The journal of physical chemistry. B Vol. 115; no. 42; pp. 11993 - 12000
• Main Authors: Borbone, Fabio, Carella, Antonio, Roviello, Antonio, Casalboni, Mauro, De Matteis, Fabio, Stracci, Glauco, della Rovere, Fabio, Evangelisti, Andrea, Dispenza, Massimiliano
• Format: Journal Article
• Language: English
• Published: United States American Chemical Society 27.10.2011
• Subjects: B: Macromolecules, Soft Matter; Crosslinking; Isomers; Nonlinearity; Physical chemistry; Polyurethane resins; Spin coating; Stability; Thin films
• ISSN: 1520-6106; 1520-5207
• DOI: 10.1021/jp204545k

In this paper we report the synthesis and characterization of a trihydroxylated nonlinear optical (NLO) azochromophore and its functionalization with 2,4-tolylendiisocyanate (TDI) to give an amorphous mixture of isomers that was used as a starting compound for the preparation of cross-linked electro-optic (EO) thin films. An unedited type of thermal cross-linking reaction was used, exploiting the reactivity of isocyanate groups themselves in the presence of N,N-dimethylacetamide, without the addition of any hydroxylated comonomer as usual in the preparation of polyurethanes. Thin films were prepared by spin coating and corona poled during thermal cross-linking. A d 33 value of 33 pm/V was obtained by second-harmonic generation (SHG) measurements on poled films, and an excellent stability of SHG signal was shown upon aging at 130 °C and during dynamic thermal stability measurements.