Linear, protected ?-methoxy oligo(glycerol) methacrylate (OGlyPMA) macromonomers are synthesized via anionic ring-opening polymerization of ethoxyethyl glycidyl ether (EEGE) followed by termination with methacrylic acid anhydride ($ \overline D \overline P_{\rm n} $ = 311, PDI < 1.30). The covalently bound methacrylate moiety allows the homopolymerization of OGlyPMA as well as copolymerization with low molecular weight comonomers. In homopolymerizations, macromonomers are polymerized by atom transfer radical polymerization (ATRP) yielding well-defined graft polymers ($ \overline M_{\rm n} $ = 20 00030 000 g mol-1). Acidic hydrolysis of the protecting groups releases water-soluble polyhydroxy-functional structures. First results on the copolymerization with 2-hydroxyethyl methacrylate (HEMA) are given in the final part of this work.