PHOTOLUMINESCENCE CHARACTERISTICS OF Eu³⁺ DOPED IN PHASE SEPARATED BOROSILICATE GLASS

抄録

The 6Na₂O·31B₂O₃·63SiO₂ (in mol%) glass was chosen. The photoluminescence (PL) characteristics of Eu³⁺ doped in the glass, which was subjected to different phase separated heat treatments, were investigated systematically. It was found that PL intensity of ⁵D₀→⁷F₂ transition of Eu³⁺ increased with phase separation developing. Furthermore, the maximum PL intensities obtained by the different heat treatment processes seem to depend on the morphology induced by phase separation, the droplet morphology having the advantage over the interconnected one with the PL intensities of 6.4 and 5.5 times as high as that in the as-cast sample, respectively. The mechanism of enhancement of the PL intensity was then discussed on the basis of the derived expression of the PL intensity. It was concluded that the induced interface after phase separation, engendering significant increase in light scattering intensity and thereby notable increase in the population of Eu³⁺ on the ⁵D₀ energy level, accounted for considerable increase in the PL intensity. On the other hand, from the emission intensity ratio of the ⁵D₀→⁷F₂ to ⁵D₀→⁷F₁ transitions (R) of Eu³⁺, the phases into which Eu³⁺ segregated after various phase separation processes were estimated.