The photochemical and thermal cis-trans isomerization of azo chromophores which were either dissolved, a pendant group or part of a crosslink in rubbery poly(ethyl acrylate) networks has been investigated. The thermal relaxation behaviour of the azo compound in the networks depends on the crosslinking density and can be described by a WLF-equation with the same parameters as found for non-crosslinked polymers. For stretched polymer films with azo-aromatic crosslinks, a photomechanical effect, i.e., a reversible contraction and expansion was observed, which is mainly ascribed to conformational change of the azo chromophore.