Long-lasting phosphorescence of transparent surface-crystallized glass-ceramics

Transparent surface-crystallized glass-ceramics with molar compositions of 43SiO(2)-2B(2)O(3)-30SrO-25MgO-0.05Eu(2)O(3)-0.8Dy(2)O(3) (sample GC-A) and 43SiO(2)-2B(2)O(3)-24SrO-6CaO-25MgO-0.05Eu(2)O(3)-0.8Dy(2)O(3) (sample GC-B) were prepared by heat-treating the mother glasses at 850 degrees C for 10 h. The precipitated phases in both glass-ceramics were (Sr1-xCax)(2)MgSi2O7, in which Eu2+ and Dy3+ ions were incorporated. Phosphorescence with emission peaks at 470 and 480 nm that is due to the 4f(6)5d-4f(7) transition of Eu2+ ions was observed from samples GC-A and GC-B, respectively. The phosphorescence lasted for >5 h at room temperature.