First, we investigated differences between networks synthesized by our method (PEG-2 and CN5-3) with networks synthesized according to Sakai et al. (PEG-1). In addition to the different linkage mechanisms, it should be noted that the synthesis according to our method was carried out in the less polar solvent (toluene-d8 versus D2O). The polymer concentrations during the syntheses were comparable (~3c*, with neglectable small variations, see Table ), but our oxazinone terminated tetra-stars are not compatible with water-based gel synthesis, precluding the corresponding control experiment. PEG-1 was synthesized in water according to Sakai et al., whereas PEG-2 and CN5-3 were synthesized in toluene according to our method. Note that the significant increase in the apparent defect fraction for the Sakai network arises mainly from HDO, which can be formed by interaction of D2O with moisture, b) corresponding RDC values and the fraction-weighted average RDC of the presented samples and connectivity fractions.