Large compound particles formed in water by polyglycidol-poly(propylene oxide) -polyglycidol, PG-PPO-PG, block copolymers are investigated by small-angle neutron scattering. The present PG-based copolymers differ from the familiar Pluronic copolymers in that the poly(ethylene oxide) blocks of the latter are substituted by structurally similar blocks of PG bearing a hydroxyl group in each monomer unit. The temperature and concentration intervals covered in this study were 15-60 degrees C and 2-33 wt %, respectively. The results reveal that in the interior of the large particles slightly prolate spherical PPO domains coexist with individual chains. The latter are not involved in the formation of the PPO domains but mediate interdomain interactions via hydrogen bonding. The dimensions of the two types of scattering objects as well as the aggregation number of the PPO domains were determined. The number of the PPO domains per large compound particle was estimated at different temperatures using earlier light scattering data. At higher concentrations the PPO domains are arranged in a cubic lattice. Their surface is sharper and more distinct at 60 degrees C than at 40 degrees C.