Study On Preparation, Structure And Properties Of Optical Functional Al₂O₃-B₂O₃-SiO₂ System Glasses

Al₂O₃-B₂O₃-SiO₂ glass was one of important inorganic materials.It possessed good physical and chemical properties,and the raw materlas are cheap.Therefore,it had wide application in chemical engineering,information display,and nuclear waste treatment and so on.This work introduced Al₂O₃-B₂O₃-SiO₂ glass system as the matrix,and focused on two research points.One point was to solve some technical problems of flat alumino-borosilicate glass prepared by micro-float process,which had important energy saving application in fire-resistance,information display and photovoltaics.The other point was to develop a kind of rare earth ions doped luminescence glasses which possessed good thermal stability,could emit white ligh under UV-light excitation and had potaintial application in White-LED area.First,this thesis reviewd the studies of three aspects as following:(â…°) the structure investigations of Al₂O₃-B₂O₃-SiO₂ glasses,(â…±) the investigations of flat alumino-borosilicate glasses prepared by micro-float method,and(â…²) the investigation progress of white ligh emission glasses.Second,the alumino-borosilcate glasses,rare earth ions doped luminescence aluminoborosilicate glasses and rare earth ions doped luminescence oxyfluoride aluminoborosilicate glass ceramics were prepared by melting-annealing/quenching/thermal treatment method.The micro-structure,optical and thermal properties were mearsured by XRD,TEM,NMR,IR,XPS,DTA,PL and so on.The details were listed as following:(1) The effects of temperature system on preparation of alumino-borosilcate glasses by melting and annealing method were investigated.The alumino-boroslicate glasses with good melting quality,low coefficient of thermal expansion,high transmission of visible ligh,and low density were prepared.The effects of mixed alkaline earth oxides on crystallization property of alumino-borosilicate glasses were also investigated.The results indicated that the crystallization degree was reduced by introducing mixed alkaline earth oxides to alumino-borosilicate glasses.The tin penetration at bottom surface of float alumino-borosilicate glasses was studied by a lab-scale float apparatus.SEM image showed that a typical tin penetration layer could be detected above 850℃.The tin penetration depth increased with increasing reaction temperature from 850 to 950℃,while it decreased with further increasing reaction temperature from 950℃to 1050℃.(2) Two serieses samples of Eu-Dy and Tm-Dy ions co-doped aluminoborosilicate glasses were prepared by melting-annealing method with appropriate temperature system.The two serieses samples emited white light under UV light excitation.Meanwhile,the effects of concentration ratio among different rare earth ions,total concentration of rare earth ions and excitation wavelength on chrominance of white ligh emission were investigated in this work. The effects of glass matrix composition on white light huninescence properties of Tm-Dy ions co-doped aluminoborosilicate glasses were studied in the thesis.The results showed that the chroinance of white light emission was not affected by changing glasses matrix composition and the chroinance of white light emission is stable.The transition mechanism between different excitation energy levels in Tm-Dy ions co-doped aluminoborosilicate glasses was also studied.It indicated that an energy transfer progress of Tm³⁺→Dy³⁺ may exsit between Tm-Dy ions.The probability of the energy transfer progress could be affected by the separation degree of Tm-Dy ions in glass matrix.On the other hand,the chrominance of white ligh emission is stable even though the Tm-Dy co-doped aluminoborosilicate glass had been thermally treated on 530℃for 2～32 h,and the luminescence intensity of the samples did not decrease after thermal treatment.It indicated that the glass possessed good thermal stability.(3) Eu₂O₃ doped aluminoborosilicate glasses were prepared by melting-annealing method in air.The reduction of Eu³⁺→Eu²⁺ was observed the samples prepared in air atmosphere. Since Eu³⁺ and Eu²⁺ ions were important actors of red and blue light emission which could synthesize white light,the effects of network modifier cations,network former cantions and thermal treatment on the reduction reaction were systematically investigated in the work. The results showed that the optical basicity of glass matrix and three dimension network structure of glass played important roles in the reduction reaction.The reduction degree was enhanced by the decrease of glass optical basicity and the stabilization of glass three dimension network structures.Meanwhile,when the optical basicity of introduced univalent network modifier cations was equal to that of bivalent network modifier cations,the existence of bivalent network modifier cations was more benefit for the Eu reduction in air.(4) Futhermore,the effects of network anions on the Eu reduction in aluminoborosilicate glasses prepared in air were investigated in this thesis.Eu₂O₃ doped oxyfluoride aluminoborosilicate glasses were prepared by melting-quenching method in air.The reduction of Eu³⁺→Eu²⁺ was observed in the samples prepared in air atmosphere.The Eu reduction reaction was enhanced by the increase of concentration ratio between F^-/O^2- ions. The effects were related with the changing of "electron donor powers" of glass matrix with different network anions.The "electron donor powers" of glass matrix would decrease with increasing of the electronegetivity of network anions,which resulted in preferable of Eu reduction.(5) The preparation,structures and properties of rare earth ions doped oxyfluoride aluminoborosilicate glasses and glass ceramics were investigated in this thesis.The Eu₂O₃ doped oxyfluoride aluminoborosilicate glasses and glass ceramics were prepared by melting-quenching and melting-thermal treatment method in air.The effects of thermal treatment temperature and time on the crystallization behavior and optical properties of Eu₂O₃ doped oxyfluoride aluminoborosilicate glasses were investigated.Transparent oxyfluoride aluminoborosilicate glass ceramics with Ba₂LaF₇ micro-crystalline were obtained by thermal treatment under appropriate temperature and time.The crystallization behavior affected the optical properties of Eu₂O₃ doped glasses to some extent.The emission intensity ratio between Eu²⁺ and Eu³⁺ ions was changed with crystallization behavior.Moreover,the effects of Eu₂O₃ concentration on the crystallization behavior and optical properties of oxyfluoride aluminoborosilicate glasses were studied.The Ba₂LaF₇ crystallization degree decreased with the increase of Eu₂O₃ concentration and decrease of La₂O₃ concentration.Meanwhile,the degree of variation of emission intensity ratio between Eu²⁺ and Eu³⁺ ions decreased.The ⁵D₁→⁷F₂ transition emission was observed in the samples been thermally treated with low Eu₂O₃ concentration,while it could not be observed in the samples with high Eu₂O₃ concentration.(6) The effects of crystallization behavior on the rare earth ions doped oxyfluoride aluminoborosilicate white light emission glasses were investigated.The Tm₂O₃ and Dy₂O₃ co-doped oxyfluoride aluminoborosilicate glasses and glass ceramics were prepared by melting-quenching and melting-thermal treatment method in air.The thermal treatment process affected the luminescence intensity,but it would not affect the chroinance of white light emission.The Ba₂LaF₇ crystallization degree decreased with the increase of Tm₂O₃ and Dy₂O₃ co-doping concentration and decrease of La₂O₃ concentration.Moreover,the Tm₂O₃ and Dy₂O₃ co-doping concemtration quenching point of quenched samples was about 1 mol.%, and that of thermal treated samles was 2 mol.%.Meanwhile,the chroinance of white light cmission was stable with different Tm₂O₃ and Dy₂O₃ co-doping concentration.