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Radioactive waste immobilization is a means to limit the release of radionuclides from various waste streams into the environment over a timescale of hundreds to many thousands of years. Incorporation of radionuclide-containing wastes into borosilicate glass during vitrification is one potential route to accomplish such immobilization. To facilitate comparisons and assessments of reproducibility across experiments and laboratories, a six-component borosilicate glass (Si, B, Na, Al, Ca, Zr) known as the International Simple Glass (ISG) was developed by international consensus as a compromise between simplicity and similarity to waste glasses. Focusing on a single glass composition with a multi-pronged approach utilizing state-of-the-art, multi-scale experimental and theoretical tools provides a common database that can be used to assess relative importance of mechanisms and models. Here we present physical property data (both published and previously unpublished) on a single batch of ISG, which was cast into individual ingots that were distributed to the collaborators. Properties from the atomic scale to the macroscale, including composition and elemental impurities, phase purity, density, thermal properties, mechanical properties, optical and vibrational properties, and the results of molecular dynamics simulations are presented. In addition, information on the surface composition and morphology after polishing is included. Although the existing literature on the alteration of ISG is not extensively reviewed here, the results of well-controlled static alteration experiments are presented here as a point of reference for other performance investigations.

Water or acid soaking surface treatments have been shown to increase the mechanical strength of soda‐lime silicate (SLS) glasses. This increase in strength has traditionally been attributed to effects related to residual stress or changes in fracture resistance. In this work, we report experimental data that cannot be explained based on the existing knowledge of glass surface mechanics. In dry environments, annealed and acid‐leached SLS surfaces have comparable crack initiation stress and fracture stress as measured by Hertzian indentation and biaxial bending tests, respectively. Yet, in the presence of humidity, acid‐leached surfaces have higher failure stress than the annealed surfaces. This apparent enhancement in the crack resistance of the acid‐leached surface of SLS glass in humid environments supports the hypothesis that acid‐leached surface chemistry can lower the transport kinetics of molecular water to critical flaws.

Anecdotal and empirical evidence suggests that heat strengthening treatments compromise the wear and scratch resistance of soda lime silicate (SLS) glass. This can be problematic when trying to clean inorganic debris from the glass surface which can result in scratches degrading the optical clarity of the glass surface. Interestingly, past work using a ball‐on‐flat tribometer showed that SLS has peculiar wear behaviors as a function of relative humidity (RH). In dry conditions, inorganic counter surfaces abrade SLS. In contrast, in high humidity conditions, SLS substrate exhibits wear resistance for a variety of inorganic counter‐surface materials. The focus of this fundamental study is to investigate the hardness, indentation fracture resistance (IFR), and wear resistance of SLS float glass with various thermal treatment histories—as‐received (exposed to ambient lab air for about a year), annealed, heat strengthened, and thermally tempered—as a function of humidity using Vickers indentation and ball‐on‐flat tribometer. Several hypotheses were considered, and it was proposed that Si‐O bond parameters, specifically strained bonds, may play an important role in the mechanochemical wear behavior of soda lime glasses at high humidity conditions.