Formation of Sm2+ ions in sol-gel-derived glasses of the system Na2O-Al2O3-SiO2

Samarium ions (Sm2+) incorporated into aluminosilicate glasses by a sol-gel process showed persistent spectral hole burning at room temperature. Gels of the system Na2O-Al2O3-SiO2 synthesized by the hydrolysis of Si(OC2H5)(4), Al(OC4H9)(3), CH3COONa, and SmCl3 . 6H(2)O were heated in air at 500 degrees C, then reacted with H-2 gas to form Sm2+ ions. Whereas Al3+ ions effectively dispersed the Sm3+ ions in the glass structure, Na+ ions were not effective, The Al2O3-SiO2 glasses proved appropriate for reacting the Sm3+ ions with H-2 gas and exhibited the intense photoluminescence of Sm2+ ions. The reaction of Sm3+ ions with H-2 in the Al2O3-SiO2 glasses was determined by first-order kinetics, and the activation energy equaled 95 kJ/mol. At 800 degrees C, the maximum photoluminescence of the Sm2+ ions was achieved within 20 min.