Following our earlier papers [1-7] on star formation from oligo(oxyethylene)alcoholates as arms precursors and diglycidyl ethers as core the course of reaction of monomethyl ethers of poly(ethylene glycol) (as alcoholate, MPEG-O-circle minus) and diglycidyl ether of neopentyl glycol (DGNG) has been studied. Epoxy groups (E) react not only with primary alcoholates (p-O-circle minus), from the starting MPEG, but also with secondary -O-circle minus (s-O-circle minus) emerging in this reaction. Concentrations of both kinds of alcoholates have separately been determined by H-1 NMR. Direct measurements by H-1 NMR of concentrations of reagents allowed to follow the stars formation and compare these results with kinetic data observed by MALDI-TOF-ms and SEC. There are two major different populations of the intermediately formed stars, namely with and without E. The former are much more reactive then the latter. It has been observed that for some stars the steady state appears, resulting from their fast formation and slow consecutive reactions. (C) 2015 Elsevier Ltd. All rights reserved.