  A generalized model taking into account the photoisomerization influence on
the nematic ordering is presented. This generalized theory is used to
investigate the effect of the nonextensivity on the concentration dependence of
the long-range order parameter. The q-dependent variation of the concentration
of cis-trans isomers and of the order parameter with the time of exposure to
the illumination is investigated within nonextensivity. It is also shown that
for sufficiently long exposition of the mesophase to the illumination the
nematic phase cannot disappear for some value of the entropic index, coming
from Tsallis statistics. Moreover it is shown that long range interactions or
the fractal structure in the liquid crystalline system might affect the
characteristics of the phase transition in the physical system. We think
therefore that this conclusion might shed light on the interaction potential
energy terms in the similar system in future possible experiments, even to be
performed on new objects with different symmetries.
