We demonstrate optical storage by means of trans-cia isomerization within melamine monomers as well as within the corresponding cross-linked melamine resins using holographic grating experiments. The melamine monomer is chemically linked with a photoaddressable azobenzene group. By thermal treatment the semicrystalline monomers can be converted into the amorphous cross-linked resin. Both the monomer material and the cross-linked resins display a photoinduced trans-cis isomerization of the azo groups, a stable photoorientation under irradiation with linear polarized light, and a stable storage of holographic gratings. The photokinetics in the different environments are found to be similiar but somewhat faster for the amorphous resins.