Titania nanotube arrays were synthesized via anodic oxidation of titanium foils in glycerol electrolyte containing NH₄F at anodization voltage ranging from 10 V to 30 V. The structural parameters of self-organized periodic arrays of titania nanotubes were determined by small-angle neutron scattering and scanning electron microscopy techniques. Transmission electron microscopy and electron diffraction studies of single-standing nanotubes revealed the presence of nanocrystalline titanium oxide phases with oxidation states lower than +4 (TiO, Ti₂O₃). Several assumptions on growth and self-organization mechanism of nanotube arrays have been made.