OPTICAL INVESTIGATION OF EU3- EVIDENCE FOR 2 DIFFERENT SITE DISTRIBUTIONS( IN A SODIUM BOROSILICATE GLASS )

A borosilicate glass of molar composition 0.01Eu(2)O(3) . 0.99(25Na(2) O . 50B(2)O(3) . 25SiO(2)) has been studied through the optical spectr oscopy of the Eu3+ ion. Absorption and excitation spectra, fluorescenc e line narrowing, and time-resolved spectroscopy show that the impurit y ions are accommodated in two different site distributions, one relat ed to a silicate environment, and the other one related to a berate en vironment. These results have been corroborated by crystal-field calcu lations and comparison with the crystal-field parameters for the Eu3ion in silicate and berate glasses. The presence of phonon sidebands i ndicates strong coupling with high-frequency Si-O and B-O stretching v ibrational modes.