A. Shishido et al., RAPID OPTICAL SWITCHING BY MEANS OF PHOTOINDUCED CHANGE IN REFRACTIVE-INDEX OF AZOBENZENE LIQUID-CRYSTALS DETECTED BY REFLECTION-MODE ANALYSIS, Journal of the American Chemical Society, 119(33), 1997, pp. 7791-7796
Optical switching behavior of low-molecular-weight and polymer azobenz
ene liquid crystals (LCs) was explored by means of reflection-mode ana
lysis. Reflectivity changed on pulse irradiation under various conditi
ons of orientations of LC molecules with respect to incident probe lig
ht, either s-polarization or p-polarization. For the low-molecular-wei
ght LCs, we obtained a response time of 100 mu s, which was very simil
ar to that observed in the transmission-mode analysis, while we observ
ed a decay time of 1 ms, which was significantly shorter than that obs
erved in the transmission-mode analysis. The fast decay may be due to
diffusion and reorientation processes which are characteristic of the
reflection-mode analysis. For the polymer LCs, we observed a much slow
er decay than those for the low-molecular-weight LCs.