Fig. 1. Crystallization of glass samples for in situ precipitation of SrAl2O4 crystallites. (a) and (b) DSCs of B25–B40 samples (Tc1 and Tc2 represent two crystallization peaks of glass, respectively). (c) XRD patterns of different B2O3 doping; inset presents glass sample picture. (d) Tra spectrum of B25–B40 glass samples. (e) and (f) FTIT and FTIA spectra of glass samples, respectively. (g) Structure schematic representation of the samples. (h₁)–(h₆) The microcrystals patterns of SrAl2O4 crystallites of B30 sample, in which (h₁) and (h₃) are SEM patterns of glass surface; (h₂) shows the size distribution of the crystallite’s particles; (h₄) is TEM observation; (h₅) and (h₆) are HRTEM observations.

Fig. 2. PL properties of SrAl2O4 glass at room temperature. (a) PLE and PL spectra of B25 and B30 glass samples. (b) PLE and PL spectra of B35 and B40 glass samples. (c) Abs spectra of B25–B40 glass samples. (d) Photographs of B25–B40 glass samples under UV excitation and after 5 min UV light irradiation.

Fig. 3. LPL property and mechanism in the SrAl2O4 embedded B30. (a) TRL curve of SrAl2O4 glass after irradiation of UV light for 5 min. (b) PLE and PL spectra of B30:0.01Eu, 0.005Dy, and B30:0.01Eu samples. (c) Emission spectra of B30:0.01Eu, 0.005Dy, and B30:0.01Eu samples were first irradiated under ultraviolet light for 5 min and then excited with 980 nm light after decay time t=30  h. (d) TRL curve of B30:0.01Eu2+. (e) Diffuse reflection spectrum of the B30; inset lists the parameters about the TRL trap in (a). (f) PSL, TRL, and LPL mechanisms of the SrAl2O4 glass. (g) LPL decay curves of B30 and commercial SrAl2O4 powder; inset is LPL decay spectrum of B30 at room temperature. (h) LPL pictures of B30 and commercial SrAl2O4 powder after stopping UV irradiation.

Fig. 4. Glass pictures of writing, reading, and erasing processes of optical information.

Table 1. Assignment of FTIT and FTIA Spectra of Samples