Crosslinked polymer materials for nonlinear optics. 2. Polyurethanes bearing azobenzene dyes

Abstract

A cross-linked nonlinear optical urethane polymer is prepared from 4-[ (2-hydroxyethyl)sulfonyl] -4'-[N,N-bis(2-hydroxyethyl)amino] azobenzene (1) and toluene diisocyanate by simultaneously corona poling and cross-linking at 145 °C for only 30 min. This material shows very promising results as NLO material: SHG measurements show a resonantly enhanced <¿33 value of 60 pm/V at 1064 nm 1 day after poling and a 34% decrease after 800 h at 70 °C. Moreover, electrooptic measurements on contact poled samples at 175 °C result in a value of the pockels constant r33 of 12.3 pm/V. Poling at 190 °C results in a decrease of less than 40 % after 100 h at 1506 C. Additional measurements show a linear interrelation between the electrooptic and the pyroelectric constant, as well as between the electrooptic constant and the dielectric polarization.

Preparation and Optical Limiting Properties of Polyurethane Containing Long Conjugated Chromophores

“…Polyurethanes exhibiting excellent mechanical and thermal properties have drawn both scientific and industrial attention. Many polyurethanes containing different chromophore groups were synthesized and their nonlinear optical properties were investigated (7)(8)(9)(10)(11)(12)(13)(14)(15). However, little attention has been devoted to optical limiting properties (16).…”

Nonlinear optical polymers with dipole moment aligned transverse to main chain

“…5 Furthermore, the crosslinking technique has been used to suppress the reorientation of NLO-phore due to molecular motion. [6][7][8][9][10][11] Recently, a new class of main chain polymer has been presented, where NLO-phore whose dipole moment is aligned transverse to the main chain backbone. 12 We have also synthesized this class of NLO polymer whose dipole moment is aligned transverse to the main chain backbone and resultant poled polymer film shows large second harmonic efficiency with its good thermal stability.…”

Preparation of the Inclusion Complex-Type Nonlinear Optical Polymer

“…However, the mobility of the polymer chain hinders the alignment of NLO chromophores, in�uencing the efficiency of electric �eld poling [12,13]. Crosslinking of the polymer which contains chromophore groups [14][15][16] or formation of interpenetrating polymer networks [17,18] has been developed to reduce the mobility of the polymer segments; consequently, the materials require longer poling times and larger poling voltages [19,20].…”