The optical switching times of liquid-crystal cells using 5CB, 5OCB and PCH5 liquid crystal materials have been
characterized as a function of applied voltage, V, and temperature, T. The transition time from 90 to 10 % transmission
scales as V-2 and is limited to 50 to 30 ns by the breakdown electric field, ~ 106 V cm-1 of the liquid crystal. The time
from the initial voltage step to 90 % transmission, delay time, decreases with increasing voltage and approaches a
constant value at higher electric fields, >105 V cm-1. Both the transition and delay times decrease with increasing
temperature. The minimum transition times at temperatures a few degrees below the nematic-isotropic temperature are
32, 32, and 44 ns and delay times are 44, 25 and 8 ns for 5CB, 5OCB, and PCH5 respectively.