Figure 2.

(Upper) Experimental (squares) and theoretical (dashed line) values of normalized electro-optic coefficient versus chromophore number density are given for the DR chromophore of Table 1. The theoretical graph corresponds to the approximation of spherical chromophore shape and W = 1.14 × 10⁶ Joule⋅(Å)⁶/R⁶, where R is given in angstroms. Experimental (diamonds) and theoretical (solid line) values of normalized electro-optic coefficient versus chromophore number density are given for the ISX chromophore of Table 1. Chromophore prolate ellipsoidal shape is explicitly taken into account. If a spherical chromophore shape is assumed then a value of W = 1.85 × 10⁷ Joule⋅(Å)⁶/R⁶ is required for simulation of the data which is approximately a factor of two higher than that required for a prolate ellipsoidal chromophore shape. (Lower) Experimental (diamonds and squares) and theoretical (solid line) value of normalized electro-optic coefficient versus chromophore number density are given for the TCI chromophore of Table 1. Chromophore shape is taken into account. Although the dipole moment for the TCI chromophore is smaller than for the ISX chromophore, the polarizability is larger so that the overall electrostatic interaction energy is comparable for these two chromophores.