New polyurethanes and polyesters for second‐order nonlinear optical applications

Abstract

New polymers for second‐order nonlinear optical (NLO) applications were synthesized and characterized. They were distinguished by the presence of chromophore groups, with various molecular hyperpolarizability values, used as pendants on substantially rigid backbones. The polymers were prepared through the reaction of tolylene‐2,4‐diisocyanate, or a suitable alkyloxyphthaloyl dichloride, with the N,N‐diethanol‐4‐(phenyl) group azo‐linked to a nitrofluorenone, nitrostilbene, nitrooxadiazole, or nitrothiadiazole moiety. The polymers exhibited good thermal stability, high glass‐transition temperatures, and an absence of crystallinity. The second‐order NLO properties of thin, transparent poled films, prepared by spin coating and thermal corona poling, were investigated for some of the polymers. The second harmonic coefficients, ranging between 18 and 25 pm/V, depended more on the alignment of the chromophore groups along the direction of the poling field than on their molecular hyperpolarizability. The temporal stability of the NLO properties of the polymers was also investigated. © 2004 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem 42: 3013–3022, 2004

Synthesis and properties of new liquid crystalline polyurethanes containing mesogenic side chain

“…The influence of spacer length on the mesomorphic behavior of polyurethane-based SCLCPs containing an azobenzene mesogenic core and their thermal properties were discussed. Other significant studies correlated with PU containing a nonlinear optical chromophore in the side chain were also presented [22,23]. The other work related to the chain extender of a segmented PU carried a mesogen in the side chain as thermoplastic liquid crystalline elastomers with interesting mechanooptical properties [24].…”

Electro-optic effect of a soluble nonlinear optical polyimide containing two different chromophores with different sizes in the side chain

“…The filtered green solid was dried at 45 o C in vacuo to yield 0.80 g (67%). 1 Synthesis of PI-II: 4 (1.0 g, 1.6 mmol of a repeating unit), 1 (0. 40 g, 0.80 mmol), 2 (0.56 g, 0.80 mmol), and DPTS (0.47 g, 1.6 mmol) were mixed in 50 mL of DCM/THF (1:3) at room temperature under argon.…”

“…[1][2][3] Polymeric materials have a strong potential for applications in telecommunications, digital signal processing, phased array radar, THz generation, etc. as active materials in photonic microdevices.…”

The synthesis and optical properties of novel fluorinated polyimides incorporated with highly electro-optic active thiazole and benzothiazole based chromophores

“…The estimated order parameter value for FPI-EHNT (V ¼ 1 À A 1 /A 0 , A 0 and A 1 are the absorbances of the polymer film before and after corona poling) was 0.24, showing good poling efficiency. During the corona poling process, the chromophores reorient in the polymer so that their dipole moments is along the field direction which is parallel to the incident light, resulting in the reduction of the peak absorbance of the incident light perpendicular to the film [34,35]. Similarly according to the absorbance change, the order parameter values for FPI-EHNBT, PFPI-EHNT and PFPI-EHNBT were estimated to be 0.25, 0.23 and 0.23, respectively.…”