Radiation-induced processes in alkali-alumina-borate glass-ceramics doped with Cr3+ ions

Abstract

Alkali-alumina-borate glass-ceramics doped with Cr3+ ions are successfully synthesized by the melt quenching technique. LiAl7B4O17:Cr3+ nanocrystals are formed in the glass host during the subsequent one- and two-stage isothermal treatments above the crystallization temperature of the nanophase. For the samples of the initial and heat-treated glass, absorption spectra are obtained containing two absorption bands that are shifted to the short-wave region after the heat treatment. The impact of the electron flux (absorbed dose of 300 kGy) leads to an increase in the optical density and color center formation. There are a wide emission band appears in the blue-green region of the spectrum (λ = 463 nm), the nature of which is possibly due to the luminescence of the borate host and series of R lines in the chromium ions in the cathodoluminescence (CL) spectra of heat-treated glass-ceramics. The optimal annealing time is determined at which the maximum value of the absolute quantum yield reaches of ≈ 40%. The luminescence decay kinetics at 463 nm is fitted by the sum of the exponential and the hyperbolic approximation. The decay time for all samples is about 200 µs. In the red spectral region (λmax = 699 nm), the luminescence decay kinetics is complex and is described by the sum of 3 exponentials and a second-order hyperbola with decay times of 0.3; 5 ± 1 ms; 10 – 27 ms, respectively. The dynamics of the growth of the decay time with increasing annealing time is manifested. Issues related to the nature of possible processes after pulse electronic excitation are discussed.