  Nematic solids respond strongly to changes in ambient heat or light,
significantly differently parallel and perpendicular to the director. This
phenomenon is well characterized for uniform director fields, but not for
defect textures. We analyze the elastic ground states of a nematic glass in the
membrane approximation as a function of temperature for some disclination
defects with an eye towards reversibly inducing three-dimensional shapes from
flat sheets of material, at the nano-scale all the way to macroscopic objects,
including non-developable surfaces. The latter offers a new paradigm to
actuation via switchable stretch in thin systems.
