Optical and nonlinear optical properties of an octasubstituted liquid crystalline copper phthalocyanine

The optical and nonlinear optical properties of an octasubstituted, liquid crystalline copper phthalocyanine, which was synthesized by the reaction of 1,2-dibromo-4,5-bis[dodecanoxymethyl]-benzene with a small excess of CuCN in dilute anhydrous N,N′-dimethylacetamide solution, are described. The ratio of the excited to ground state absorption cross-section (κ = σex/σ0) and the linear optical absorption coefficient of the compound were measured in dry toluene solution; their values were about 2.4 ± 0.5, and 1.4 cm−1, respectively. In the solid state the compound shows signs of irreversible thermal damage when illuminated by laser at the lowest energy per pulse setting used. In solution, the values of both the nonlinear absorption coefficient and the third-order nonlinear susceptibility decreased with increasing incident intensity, this being indicative of saturation effects arising from higher triplet excitations.