旭硝子股份有限公司

Understanding the structure-property relationships in glasses remains challenging owing to their structural complexity, especially in multicomponent practical glasses. In this work, neutron diffraction with isotopic substitution was employed to investigate lithium coordination environments in halide (chloride and/or bromide)-doped borate glasses, which exhibit variations in lithium-ion conductivity associated with anion mixing. Lithium-specific neutron pair distribution function analysis reveals that the conductivity enhancement in oxide-halide mixed glasses originates from the breaking of one short Li-O bond and the formation of two longer Li-halogen bonds. The formation of LiO3Cl2 and LiO3Br2 units is observed in chloride- and bromide-doped glasses, respectively, whereas a glass containing equal amounts of chloride and bromide exhibits LiO3ClBr units in addition to LiO3Cl2 and LiO3Br2 units. These results suggest that the coexistence of multiple lithium-oxygen-halogen polyhedral units hinders lithium-ion migration, leading to reduced ionic conductivity in halide-halide mixed glasses. This work provides new insights into the structure-property relationships in lithium-ion conducting glasses through lithium-specific structural analysis.

The coefficient of thermal expansion (CTE) is a critical property for oxide glass when used as a sealing material or carrier substrate, as matching the CTE with that of other materials is essential to prevent deformation, warping, and damage at the interface. The CTE is typically controlled by adjusting the glass composition; however, it is also influenced by the cooling rate during the production process. Nevertheless, the effect of cooling rate on the CTE of oxide glass materials has rarely been reported. In this study, the CTE and its dependence on cooling rate were experimentally investigated for a series of sodium aluminosilicate glasses with the composition (, Ca, Mg). The measurements were conducted at cooling rates of 1 and 100 K/min. Consequently, the effect of cooling rate was found to be more pronounced in -lean glasses, while it was insignificant for glasses with [ ] []. To elucidate the mechanism underlying the influence of content on the cooling rate dependence of the CTE, molecular dynamics (MD) simulations were conducted using two methods to estimate the CTE. The first method involved heating simulations to evaluate the volume change with temperature, while the second method measured fluctuations in enthalpy and volume to determine the CTE. The effect of cooling rate was investigated by performing MD simulations at four cooling rates: 0.1, 1, 10, and 100 K/ps, for two contrasting glass compositions, and , in . Consequently, the experimental trend-where the glass with is less sensitive to the cooling rate-was successfully reproduced by both methods when the glass structures were sufficiently equilibrated prior to measuring the CTE. Microstructure analyses revealed that doping stabilizes calcium coordination in the glass, thereby reducing the influence of cooling rate on the CTE. This may be attributed to the tendency of alkaline-earth ions to localize around aluminum segregation.

Hypervelocity impacts of small objects, such as space debris, pose significant challenges to the structural reliability of glass due to the extreme stresses and crack propagation they induce. While conventional optical techniques can qualitatively observe stress wave propagation, quantitative evaluation of stress fields and their association with fracture mechanisms remains a critical gap. This study aims to develop and validate a novel in situ photoelastic imaging method for quantitatively analyzing stress wave propagation behavior in glass under hypervelocity impact conditions. A new combined experimental and analytical system was developed using a two-stage light-gas gun to conduct hypervelocity impact experiments on silica glass plates (dimensions: 60 × 60 × 15 mm3). Both linear- and circular-polarized photoelastic images were obtained during the experiments using synchronized high-speed cameras. Time-dependent stress fields were calculated via an integrated photoelasticity approach using the onion-peeling method, which was reformulated into an integral representation to accommodate general axisymmetric conditions. The proposed analysis method successfully determined time-dependent stress-fields in impacted glass plates. Longitudinal stress waves exhibited wavelength elongation due to mechanical responses near the elastic limit under hypervelocity conditions. Observations also revealed dynamic interactions between stress wave propagation and crack initiation, highlighting the critical role of back-surface-reflected stress waves in fracture initiation. This study demonstrates the utility of in situ photoelastic observation combined with quantitative analysis for exploring stress wave behavior and subsequent fracture mechanisms in glass. The proposed method has the potential to advance the understanding of dynamic material behavior and improve the design and reliability of glasses in high-energy applications, such as space debris protection.

Determining halogen concentrations in inorganic materials is becoming increasingly important to satisfy environmental regulations. However, quantifying chlorine using laser ablation-inductively coupled plasma mass spectrometry (LA-ICP-MS) is challenging, despite the merits of this method. We propose a method for determining the chlorine concentration in glass using femtosecond LA with a scanning galvo mirror system, coupled with tandem ICP-MS (ICP-MS/MS). Hydrogen was introduced into the collision-reaction cell to eliminate mass spectral interferences (quadrupole 1: 35Cl+ (m/z 35) -> quadrupole 3: 35ClHH+ (m/z 37)). A 1 x 1 mm2 ablation area was used to minimize sample heterogeneity. Using the proposed method with standard reference materials (SRMs) 610, 612, 614, and 616 (National Institute of Standards and Technology) as calibration samples, we determined the chlorine concentration in BAM-S005-A, a standard glass reference material with a composition similar to that of the SRM 61x series. The determined value of 244 +/- 4.5 mu g g-1 (n = 6, average +/- 95% confidence interval) is in excellent agreement with the certified concentration (247 +/- 33 mu g g-1), demonstrating the high accuracy and low uncertainty of the method. The proposed method enables rapid analysis (within 10 min) and does not require harmful reagents or complicated pre-treatment. This approach can be readily extended to other materials, supporting safer, faster, and more reliable halogen analysis across research and industry settings.

This study develops a method for selectively laminating decorative and functional layers onto complex-shaped glass surfaces using a film-transfer technique. In this approach, a film coated with a thin layer is molded to the glass surface, and the desired layer is subsequently transferred by peeling off the film. This method was evaluated by examining the lamination of a specially designed adhesive layer onto a glass substrate curved in three axes, confirming successful bonding without damage. Selective lamination without masking requires precise design of the printed shapes on the film. Finite element analysis was utilized to predict the positions of the transferred areas, with these predictions informed by dynamic friction coefficients at each contact surface. By integrating actual measured values of these coefficients into the predictions, the decorative layer shapes on the film were corrected. The transferred decorative layer onto a triaxially curved glass achieved a maximum shape error of 3.18 mm across a width of 207.1 mm, demonstrating the effectiveness of the proposed method.