Luminescent probing methods were employed to investigate the interaction of the Ti-O chains of polytitanasiloxane with europium ions in the mixture of ethanol and water. The UV-vis absorption, the luminescence intensity, and the luminescence lifetimes of the Eu3+ ions in PTS solutions were all found to increase with the increase of TBT/TEOS molar ratio. The results indicated that the incorporation of TBT can result in the increase of absorption energy of the Ti-O group by near-UV excitation and in the increase of energy transfer to the metal ion, and that the Ti-O chains due to the site binding of Eu3+ ions can expel six to nine solvent molecules from the first coordination solvation shell of the ion. The investigation of the energy transfer from europium to neodymium ions in polytitanasiloxane solutions revealed the formation of aggregates consisting of seven rare earth ions (together with the polytitanasiloxane countercharges).