Luminescence of, and energytransfer between Dy<SUP>3+</SUP> and Tb<SUP>3+</SUP> in NASICON-type phosphate glasses

Fluorescence of Dy<SUP>3+</SUP> and Tb<SUP>3+</SUP> and the energy transfer between them in Na<SUB>5</SUB>TiP<SUB>3</SUB>O<SUB>12</SUB> and Na<SUB>4</SUB>NbP<SUB>3</SUB>O<SUB>12</SUB> glasses have been studied. Concentration quenching of fluorescence occurs in the case of Dy<SUP>3+</SUP> at concentrations above 3 weight %, whereas in the case of Tb<SUP>3+</SUP>, it does not occur up to 5 weight %. The energy transfer from Dy<SUP>3+</SUP> to Tb<SUP>3+</SUP> is nonradiative and takes place through dipole-dipole interaction