The recently proposed lattice model for segmental orientation in elongated networks of semirigid chains is used here to study the relationshipd among true stress, deformation, orientation, and birefringence. Of particular interest are the effects of the volume fraction of polymer (in a swollen lyotropic network) and the rigidity of the network chains (measured by the axial ratio of Kuhn segments of the chains) on stress-strain and stress-birefringence behavior. The elastomeric and optical behavior of the networks in isotropic and nematic states and networks undergoing phase transformation are thus characterized. Illustrative numerical analyses are also presented.