  This paper explores different photo-bending shapes in polydomain nematic
glass. The motivation is to explain the phenomenon in experiment [1] under
polarized light in which a nematic film curls into an circular arc, like part
of a cylindrical surface. Polarized light triggers photo-isomerization and
therefore makes liquid crystals (LCs) contract along their directors. We apply
the Sachs limit to homogenize the deformation of polydomain LC glass.
Photo-strain can be either contraction or expansion through the material.
Bending shapes can be anticlastic, bowl-shaped and cylindrical affected by
Poisson ratio and illumination intensity. An explanation for the cylindrical
bend and ways to observe other shapes are given in a parameter plane.
