Nonlinear Optical Switching Properties in the Furylfulgide Aberchrome 540-Dihydrobenzofuran Derivative Pair of Photochromic Materials

Time-dependent density functional theoretical investigation has been carried out to justify the switching action of nonlinear optical properties in the furylfulgide Aberchrome 540 (FFA) and dihydrobenzofuran derivative (DHBF) photochromic pair of molecules. The effect of solvents on this switching action has also been addressed. The calculations suggest that DHBF has a higher optical coefficient compared to that of FFA. Notably, a dramatic increase in DHBF is observed in the second harmonic data, particularly in the solvent phase. The ratio of SHG tensor gradually decreases as the polarity of the solvent is decreased using a coulomb-attenuating functional irrespective of the basis sets used. An exploration of the excitation parameters suggests that high excited-state dipole moments are responsible for the observed large P value in the case of the DHBF system relative to that of the FFA system.