Sodium Calcium Silicon Is A High Degree Of Crystallinity Of Transparent Microcrystalline Glass Preparation And Performance Characterization

High crystalline and transparent Yb3+-doped Na₂O-CaO-SiO2glass-ceramics were prepared. The optimum heat treatment schedule and crystallization process of the precursor glass were studied. The microstructure and luminescence behavior of the glass-ceramics were researched.In this paper, the Yb3+-doped Na₂O-CaO-SiO2glass were prepared by conventional melt-quenching methods. The optimum heat treatment schedule were analysised by differential thermal analysis （DSC） and X-ray diffraction （XRD）.The microstructure and luminescence behaviors of the glass-ceramics were studied by scanning electronic microscope （SEM）, absorption spectrum and flourescent spectrum, respectively.The results indicate that the compositions of the crystals were Na₄Ca₄Si₆O₁₈ when Na₂O-CaO-SiO₂glass were heat treated under different conditions. The optimum heat treatment schedule is glass uncleated at595℃for5h and crystallinzed at730℃for1h. When the Na₂O-CaO-SiO₂glass is heat-treated at （595℃,5h）+（730℃,1h）, the spherical crystals with gain size of about100μm are obtained, the crystallinity of the traparent glass reach up to82.93%. Glass-ceramic（B4） which was heated at595℃for nucleation, crystallized in diameter of0.5nm. Glass-ceramic（D1） crystallized in diameter of50μm with treatment of730℃for0.5h, after nucleation. Grains grew to100μm with the elongation of crystallzation time to1h. However, it remained the same with longer crystallzation time for1.5h,2h or3h. The arrangement of crystals was more compact. Degree of crystallization increased, along with macroscopic bubles in the glass matrix.The transmittance of samples AO, B4and D2are over90%,95%and80%, respectively.Because of the pores, the transmittance of sample D4reduce to70%. Both the absorption cross-section and the stimulated emission cross-section of the glass and glass-ceramics increase due to the elongation of crystallzation.With the degree of crystal crystallization increasing, luminescent intensity rises initially and then descends. Due to the pores, sample D4has the minimum luminescent intensity. Theoretical analysis shows that the fluorescece lifetime of precursor glass and glass-ceramics range from1.66to1.00ms. β_min and minimum absorbed pump intensity I_min first decreases and then increases with the heat treatment process. The pump saturation intensity Isat has a decreasing trend with the heat treatment process.The sample D2has the best comprehensive properties, which have a long flourescence lifetime （1.44ms） and the values of β_min, I_sat and I_min are0.094,10.22kW/cm²and0.96kW/cm2, respectively.