• Ceramist
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• v.10 no.3
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• pp.28-33
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• 2007

The structural and optical properties of Ni-doped transparent glass-ceramics are reviewed. The quantum efficiencies of ceramics were examined to explore suitable crystalline phase for Ni-doping in glass-ceramics. Inverse spinel $LiGa_5O_8$ have the quantum efficiency of almost 100 % at room temperature. Transparent glass ceramics containing $LiGa_5O_8$ was successfully synthesized by heat treatment of $Li_2O-Ga_2-O_3-SiO_2-NiO$ glass. Most of $Ni^{2+}$ ions in glass-ceramic were incorporated into $LiGa_5O_8$ nanocrystals. The near-infrared emission covering from the O-band to L-band (1260-1625 nm) was observed from the Ni-doped $Li_2O-Ga_2O_3-SiO_2$ glass-ceramic though it was not observed from the as-cast glass. The lifetime of the emission was about $580\;{\mu}sec$ even at 300K. The emission quantum efficiency was evaluated as about 10 % that is enough high for practical usage as gain media of optical fiber amplifiers. The figure of merit (the product of the stimulated emission cross section and lifetime) was as high as that of rare-earth-doped glasses. The broad bandwidth, high quantum efficiency and high figure of merit show that transparent glass-ceramics containing $Ni^{2+}:LiGa_5O_8$ nanocrystals are promising candidates as novel ultra-broadband gain media.

• Journal of the Korean Ceramic Society
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• v.29 no.3
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• pp.223-231
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• 1992

CaO and ZnO were added to Al2O3-SiO2 binary system respectively as flux, then ZrO2 and TiO2 were applied as nucleating agent to these CaO-Al2O3-SiO2 and ZnO-Al2O3-SiO2 ternary system glass. The transparency could not be kept in CaO-Al2O3-SiO2 system glass, whereas the transparent glass-ceramics were prepared in ZnO-Al2O3-SiO2 system glass containing ZrO2 as the nucleating agent. At this time the optimum heating temperatures for the nucleation and the crystal growth were 78$0^{\circ}C$ and 97$0^{\circ}C$. The sizes of the precipitated crystals in the transparent glass-ceramics were below 0.1 ${\mu}{\textrm}{m}$, and their light transmissibilities were more than 80%.

• Ceramist
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• v.10 no.3
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• pp.48-54
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• 2007

Glass-ceramics transparent above $10\;{\mu}m$ in the infrared, have been synthesized. They are based on germanium and antimony sulphides or selenides associated to alkali halides. They are prepared by heating glass samples at temperatures above the glass transition, as a function of time. Ceramisation can be controlled, so that sub-100 nm crystals are generated in the glass matrix. Then, low light scattering is achieved and the transparency window of the original glass is maintained. When gallium sulphide is added, glass ceramics can be doped with rare-earth ions. Emissions from the $^4F_{3/2}$ and $^4I_{13/2}$ of $Nd^{3+}$ and $Er^{3+}$ ions, respectively, are more intense in glass-ceramics, as compared to their vitreous counterpart. Examination of band profiles and decaytimes show that rare-earth ions are embedded in both crystalline and glassy environments.

• Journal of the Korean Institute of Electrical and Electronic Material Engineers
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• v.29 no.2
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• pp.101-105
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• 2016

The basic characteristics of glass are highly fragile and brittle consequences the ultimate purpose of glass manufacturing is to make a transparent glass with complex shape. In order to solve this problem, mechanical properties of glass can be increased by crystallization of its amorphous glass. However, glass-ceramics has become opaque through crystallization process due to the distracted interface of glass by precipitated particles. This study has been investigated thermal processing conditions of LAS transparent glass-ceramic by using DTA (differential thermal analysis), in order to control size of precipitated particle and then fabricate transparent glass-ceramic. DTA indicated that crystallization peak area was declined with increased nucleation temperature. Subsequently, we have been established optimum temperature for crystallization depending on the nucleation temperature. The transmission and thermal expansion were measured after crystallization, and the size of precipitated particle was identified in range of 20~100 nm by FE-SEM. In addition, by setting the optimized crystallization condition, with high transmission and low thermal expansion glass was synthesized through this experiment.

• Korean Journal of Materials Research
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• v.18 no.12
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• pp.678-682
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• 2008

This study investigates $Bi_2O_3$-$B_2O_3$-BaO-ZnO glass with variations of the $Co_3O_4$ content (0.25, 0.5, 1, and 2 wt%) and the interaction between transparent dielectric and Ag electrodes heat-treated at $500-560^{\circ}C$ for 30 min. The glass transition temperature, softening temperature and thermal expansion coefficient were $432^{\circ}C$, $460^{\circ}C$ and $81.4{\times}10^{-7}/^{\circ}C$, respectively. The transmittance of 0.25 wt% $Co_3O_4$ to which dielectric was added was highest and was decreased due to coloration with the addition of more than 0.25 wt%. However, without $Co_3O_4$, the transmittance of the transparent layer was decreased due to the formation of $Ba_5Bi_3$; however, the occurrence of the crystal phase decreased as a result of the addition of $Co_3O_4$. The amount of $Co^{2+}$ ions increased as the $Co_3O_4$ increased. With a maximum of $Co^{3+}$ ions, the highest transmittance was observed.

• 한국정보디스플레이학회:학술대회논문집
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• 2000.01a
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• pp.181-182
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• 2000

The glass compositions of $PbO-SiO_2-B_2O_3$ system and $P_2O_5-PbO-ZnO$ system for the transparent dielectric materials for front panel and $P_2O_5-ZnO-BaO$ and $SiO_2-ZnO-B_2O_3$ for the reflective dielectric materials for back panel of PDP(Plasma Display Panel) were investigated. As a transparent dielectric materials for front panel, $PbO-SiO_2-B_2O_3$ glass showed good dielectric properties, high transparency and proper thermal expansion matching to soda-lime glass substrate. And the reflective dielectric materials for back panel were prepared from parent glass of $SiO_2-ZnO-B_2O_3$ system and oxide filler. It was found that these glass-ceramics are useful materials for reflective dielectric layers, as those have a similar thermal expansion to soda-lime glass plate, high reflectance, low sintering temperature.

• Journal of the Korean Ceramic Society
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• v.43 no.9 s.292
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• pp.569-574
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• 2006

Transparent glass-ceramics containing fresnoite crystals have been prepared by controlled heat treatment in $K_2O-BaO-TiO_2-SiO_2$ and their nonlinear optical and luminescent properties were investigated using Maker fringe method and Spectrofluorometer. The second harmonic generation was observed in all samples and the values decreased with increasing $K_2O$ content. The luminescence of blue light at ${\sim}482nm$ could be observed and it was shown that the luminescent property was controlled by the $K_2O$ content.

• The Korean Journal of Ceramics
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• v.2 no.1
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• pp.1-10
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• 1996

Transparent conducting $SnO_2$-based thin films have been coated on float substrates such as fused quartz, and ceramic fiber cloths such as the Nexel and E-glass cloth from tin alkoxides by the sol-gel technique. Also, thin films of alternating layers of $SnO_2$ and $SiO_2$ have been fabricated by dip coating. The sheet resistance and average visible transmittance of the films were investigated in the aspect of the applications as transparent electrodes such as liquid crystal displays, photo-detectors and solar cells. The Nextel and E-glass cloths coated with antimony-doped tin oxide (ATO) had sheet resistance of as low as $20 \;ohm/{\Box}$ and $120ohm/\;{\Box}$, respectively. The promotion effects of additives as $La_2O_3$ and Pt on the ethanol gas sensing properties of the films were investigated in the aspects of the applications as an alcohol sensor and a breath alcohol checker. Possible evidence of quantum well effects in the oxide multilayers of $SnO_2$ and $SiO_2$ was investigated.

• Journal of the Korean Crystal Growth and Crystal Technology
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• v.21 no.5
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• pp.214-217
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• 2011

A fresnoite glass-ceramics has been investigating considerably because of the second order nonlinearity as well as its permanent optical nonlinearity. However, the chemical compositions of transparent glass-ceramics examined in the previous studies have been limited to adjust the composition close to fresnoite stoichiometrically. In this study, to investigate the effect of strontium ions in glass-ceramics on second order nonlinearity, $K_2O-TiO_2-SiO_2$ (KTS) glasses soaked in molten $Sr(NO_3)_2$ were prepared. Crystalline phases of the soaked glasses were measured by X-ray diffraction (XRD) as soaking times and additional heat treatment. The exchange of strontium ions into the glass was verified by Field Emission Scanning Electron Microscope (FE-SEM). And the phenomena of second order harmonic generation (SHG) was observed using Nd-YAG laser.

• Journal of the Korean Ceramic Society
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• v.27 no.2
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• pp.288-296
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• 1990

Parent glasses for the experiments were prepared to be ratio of Li2O : Al2O3 : SiO2=4.5 : 25 : 70.5 as basic components, and TiO2 and ZrO2 in the mixing ratio of 1 : 1 were added as the nucleating agents, whose contents were increased in each sample. DTA, XRD, SEM, IR were observed, and thermal expansion and transmissivities were measured for the crystallized samples under the controlled heat-treatments. The transformation temperatures and the dilatometric softening temperatures in thermal expansion curves, and also the exothermic peaks in differential thermo-analytical curves were shifted to lower temperature. The crystal phase deposited through the heat-treatment was identified as ${\beta}$-quartz solid solution with XRD and IR analysis. The crystalline phases in oopactified samples were ${\beta}$-spodumene coexiting with ${\beta}$-quartz solid solution. The samples having more than 3% nucleating agents were transparent. The crystallized grain sizes were ranged 0.05 to 0.1$\mu\textrm{m}$. The crystallized transparent samples were exceeded 85% in the transmissivity.