Utilizing a laser-heated aerodynamic levitation melting technique, we prepared a series of aluminosilicate glasses (xAl₂O₃·(100-x)SiO₂, 30≤x≤63, in molar fraction). The Vickers hardness (H_V) and crack resistance (C_R) of the glasses were investigated by a micro-hardness Vicker tester. The results show that the hardness of those glasses increases gradually with the increase of Al₂O₃ content, and the maximum hardness is 8.94 GPa as x=63. However, the crack resistance of the glasses is nonlinear with the change of composition, and the maximum crack resistance is 19.49 N as x=63. According to the results of structural analysis, the increase of atomic packing density and mean-field bond energy density can be attributed to the hardness enhancement. The reduction of the phase interface can lead to the reduction of the crack resistance, while the increase of Al₂O₃ content in the glass can result in an increase in the crack resistance. The synergy and competition between the phase interface reduction and Al₂O₃ content increase can result in a nonlinear change of crack resistance. The crack resistance does not change significantly due to the similar structures of the glasses within the mullite phase region.

Niobium oxide is widely used in glass field due to its excellent physical and chemical properties. This review summarized the fundamental research results of the application of niobium in glass and glass ceramics. The structure function of niobium oxide in glass is complex, and it mainly acts as glass network intermediate. The addition of niobium oxide into different glass systems have different effects on the network structure, thus affecting the properties of glass. The research work on niobium containing glass and glass ceramics mainly focuses on the optical and electrical properties. Niobium oxide can be used as an important oxide to replace lead oxide in lead-free glasses. Based on the research and application of niobium in glass field, the future development directions were discussed. The structure and dielectric properties of niobate glass ceramics can be improved by adding rare-earth element ions into niobate glass ceramics to adjust the crystal type.

Ultra-broadband near-infrared (NIR) luminescence of bismuth ions in glass is widely used, but the stability problem of Bi NIR centers limits its practical application. Therefore, in this work, the original local excess charge model that can effectively regulate the Bi NIR luminescence behavior was expanded and supplemented in bismuth doped yttrium aluminum-silicate glass. The statistical excess charge field around Bi was built up via either introduction of glass modifier (Y³⁺) or substitution of silicon by different glass former ions with a valence state lower than +4 (Al³⁺) in yttrium aluminumsilicate glass. As a result, the behavior of Bi NIR centers (i.e., the valence states of Bi, the intensities and peak positions of absorption and NIR emission) was determined. Also, the distribution characteristics of Bi NIR centers were proposed. Bi⁰ NIR centers are preferentially located in the multimember rings of silicon, while Bi⁺ NIR centers are situated at the interstices of silicon network. This work could solve a problem to stabilize Bi NIR centers in yttrium aluminumsilicate glass, even other alkali metals and alkali metals (Li/Na/K, Mg/Ca/Sr/Ba, etc.) aluminumsilicate glass, thus establishing the experimental and theoretical supports for the design of Bi-doped laser glasses and fabrication of fibers in future. This work also verified the effectiveness and universality of the local excess charge model, providing a strategy for stabilizing the valance state of other multivalent luminescent ions (i.e. Eu, Ce, Cu, Ag, Sn) and their distribution in glass network structure.

High silica glass fiber is widely used and has the superior properties. Acid leaching is the main existing method to prepare high silica special glass fiber. In this paper, high silica glass fiber was prepared via acid leaching and heat treatment. The structure of SiO₂-Na₂O binary glass fiber during acid leaching and heat treatment was investigated by Raman spectroscopy. The results show that the bending vibration peak and asymmetric stretching vibration peak shift to a lower wavenumber, and the peak intensity becomes weaker during acid leaching process, mainly because SiO₂ content in the fiber increases and the internal structure of the fiber changes to a chain structure. After heat treatment, the asymmetric stretching vibration peaks disappear, and the defect lines D₁ and D₂ appear, and the density of fibers changes at different heat treatment temperatures, mainly due to the condensation reaction of fiber during heat treatment.

Dual-phases glass ceramics (GCs) containing LiYF₄∶Ln³⁺(Ln=Eu, Tb, Dy) and ZnAl₂O₄∶Cr³⁺ nanocrystals (NCs) were fabricated by a conventional melt-quenching method. The structural and spectrographic characterizations indicate that Ln³⁺ can be doped into LiYF₄ lattice and Cr³⁺ can be introduced into ZnAl₂O₄ lattice, respectively. In this regard, the luminescent centers are physically separated through a spatial isolation strategy, getting rid of adverse energy transfer processes. The dual-modal luminescence of Ln³⁺ and Cr³⁺ can be thus attained simultaneously. Also, optical thermometry based on the fluorescence intensity ratio (FIR) of Ln³⁺/Cr³⁺ is performed. Under irradiation upon 377 nm, the FIR value for Tb³⁺∶⁵D₄→⁷F₅ and Cr³⁺∶²E→⁴A₂ transitions varies acutely, with a maximal relative sensitivity of 0.80%·K^-1 at 570 K. The FIR-based optical thermometry for Dy³⁺∶⁴F_9/2→⁶H_13/2 and Cr³⁺∶²E→⁴A₂ transitions is carried out, with a maximal relative sensitivity of 0.86%·K^-1 at 573 K. As a consequence, the dual-phases GCs can be an ideal medium for the spatial isolation of luminescent centers, suppressing an adverse energy transfer process and realizing an efficient dual-mode luminescence. This is beneficial to the application of FIR-based optical thermometry for GC materials.

Nano-porous glass is a multifunctional microstructure material, which is widely used in the fields of purification and filtration, biochemistry and ion selection. Also, the optical materials prepared with porous glass have some superior advantages in optics. Recent research work on nano-porous glass in the visible and near-infrared bands was reviewed. The luminescent properties of various rare-earth element ions and metal ions in porous glass were introduced, and the advantages of porous glass in preparing luminescent glass-ceramics and encapsulating carbon dots and quantum dots were demonstrated. A method of fabricating optical fibers using porous glass was described, which could be expected to break through the technical difficulties of various active optical fiber fabrication technologies. In addition, some prospects for the future development of nano-porous glass were also given.

A series of xBi₂O₃-AlPO₄-SiO₂ glasses (0≤x≤0.15) were prepared by a sol-gel process. The local structures of glasses were investigated by magic angle spinning nuclei magnetic resonance (MAS NMR) and X-ray photoelectron spectroscopy (XPS). Based on the ²⁷Al MAS NMR spectra. The results show that trere is Bi-O-Bi connectivity in all these glasses. In addition, the prepared glass is composed of AlPO₄- and SiO₂-nanodomains according to the results of ²⁷Al{³¹P} REDOR, ³¹P{²⁷Al} REAPDOR, ³¹P CT-DRENAR-BABA-xy16, and ²⁹Si MAS NMR. The addition of Bi₂O₃ promotes the increase of AlPO₄ clusters, forming the final phase, and Bi₂O₃ exists both in SiO₂ and AlPO₄ nanodomains.

The diameter distribution of high-strength glass fiber (HS2) strands and rovings was analyzed, and the influences of the average fiber diameter and the diameter distribution on the mechanical properties of HS2 glass fibers were evaluated. The results show that the tensile strength of fiber bundles and impregnated rovings decreases with the increase of the diameter when the diameter is >11μm. The tensile strength of unidirection orientated fiber reinforced plastic plates with the fiber diameters of 11-13 μm is not affected by the diameter, and the shear strength decreases with the increase of the diameter. The wide distribution and high variation coefficient (C_v) have an adverse effect on the mechanical properties of the fiber. When the average fiber diameter is 11μm, the roving tensile strength of the diameter with C_v 0.20 is 8% lower than that with C_v 0.15. The diameter distribution can reveal the forming tooling and process, and the process needs to be strictly controlled to refine the highly uniform fibers.

Borosilicate bioactive glass promises broad application prospects in biomedical field because of the controllable degradation, hydroxyapatite convertibility in situ, biocompatibility, bond-ability with hard and soft tissues, strong tissue repair and regeneration capability. This review briefly represented recent development and application of borosilicate bioactive glass and its derived materials, and some research work on the multifunctional modification of borosilicate bioactive glass via functional element doping, organic-inorganic hybrid composition, and construction of micro/nano-structure. The latest achievements in tissue repair, tumor therapy, drug delivery and other fields were summarized. In addition, the prospects and challenges of borosilicate bioactive glass were also discussed.