A new block copolymer was synthesized and characterized based on poly(ethylene oxide) (PEO) and poly(glyceryl glycerol) (PGG). The resulting polymer is found to bear two additional hydroxyl groups in every PGG repeat unit, and the nuclear magnetic resonance (NMR) characterization of PEO-PGG diblock copolymers confirms the presence of dendritic and terminal units. The results also indicate that all polymerizations result in quantitative yield and full conversion, when the degree of polymerization of PGG is adjusted to a certain limit. Characterization data for all polymers is prepared by varying the molecular weight of both PEO and PGG segments. Molecular weight determination through NMR spectroscopy is found to be error-prone due to the lack of a well-separated end-group signal.