Silicate glasses are important cultural, societal and geological materials. Geologic glasses testify for the igneous activity of the Earth and, for instance, represented important source of tools and ornamental objects during the Paleolithic. Nowadays, silicate glasses are used to build technical materials, such as smartphone screens or glass matrix for stabilizing hazardous radioactive wastes. Therefore, silicate glasses are central to the history of the Earth and of the humanity. The compositional landscape of natural and industrial silicate glasses is vast, with various elements that all influence differently the glass properties and structure. The SiO 4 tetrahedral framework, backbone of silicate glasses, is variously influenced by the introduction of network modifier metal cations or network former aluminium cations. Industrial and geologic silicate glasses further contain multivalent elements (e.g., Fe 2+/3+), rare-earth elements, and volatile elements (H, C, S, Cl, F, I) that play different roles on the glass structure and properties. This chapter proposes to review the link between the structure, the properties and the chemical composition of silicate glasses.

V 2 O 5 was introduced up to 9 wt.% in a peralkaline alkaline earth aluminosilicate glass and up to 4.8 wt.% in two sodo aluminosilicate glasses, respectively, a peralkaline and a peraluminous one. This introduction had a strong effect on thermal properties, and in particular, on glass transition and crystallization temperatures of the peraluminous glass, which dropped by 89 K, while a moderate drop of ∼20 K was observed for the two other glasses. Still, the glass stability and the glass-forming ability stayed almost unmodified. The elastic properties measured by Brillouin spectroscopy show a decrease with added Vanadium for the depolymerized alkali earth aluminosilicate and the peraluminous sodo aluminosilicate. In contrast, the elastic properties remained unchanged for the peralkaline composition. Using optical absorption, the proportion of V 5+ , which is largely dominant, was found to follow the trend predicted using optical basicity considerations. A large photoluminescence emission, centered at ∼560 nm, was found for all glasses, upon excitation in the UV edge at both ∼280 and ∼350 nm. The emission band positions were relatively insensitive to the glass composition, whereas their intensities show variations of one order of magnitude between the sodium peralkaline composition and the calcium depolymerized glass. A too-high concentration of V 2 O 5 shows a quenching effect on the emission. Polarized and cross-polarized Raman spectroscopy allowed us to identify the different environments around the V 5+ O 4 tetrahedra. The highly polarizable V 5+ O 4 tetrahedra associated with two non-bridging oxygens, vibrating at 860 cm −1 , is proposed to be responsible for the more efficient charge transfer. At the opposite end, the formation of VO 4 -AlO 4 units is proposed to quench luminescence properties. Furthermore, we observed that, upon thermal treatment, the optical properties of the glasses are significantly modified without observable structural modifications or evolution of the elastic properties.

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Chalcogenide perovskites are a promising and novel class of materials in the fields of solar cells and related subjects. However, the synthesis of thin films of these materials still is troublesome. This work attempts to utilize a phase in the Ba‐S phase system with low melting point, namely, BaS3, for the thin‐film synthesis of BaZrS3. The successful synthesis of BaS3 thin films is presented and confirmed by field‐emission scanning electron microscopy (FESEM), X‐ray diffraction (XRD), and Raman analysis. The microstructure of the synthesized BaS3 thin films shows defects and cracks and therefore needs further optimization for the use for BaZrS3 thin‐film synthesis. However, the successful synthesis of BaS3 thin films is potentially a great step toward a facile BaZrS3 thin‐film synthesis.

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On Earth, natural glasses are typically produced by rapid cooling of melts, and as in the case of minerals and rocks, natural glasses can provide key information on the evolution of the Earth. However, we are aware that natural glasses are products not solely terrestrial and that the formation mechanisms give rise to a variety of natural amorphous materials. On the Earth´s surface, glasses are scarce compared to other terrestrial bodies (i.e. Moon), since the CONTENTS-QUENCHED GLASSES 1.1 -Volcanic glasses Applications: alteration of natural glasses as analogue of nuclear waste glasses 1.2 -Lunar glasses 2 -IMPACT GLASSES 2.1 -Tektites and microtektites 2.2 -K-Pg (KT) spherules 2.3 -Younger Dryas (YD) event 2.4 -Enigmatic impact glasses 2.4.1 -LDG -Libyan Desert Glass 2.4.2 -Darwin glass 2.5 -Fulgurites 3 -OBSIDIAN 3.1 -Hydrated and altered obsidians 4 -OTHERS 4.1 -Glasses from nuclear explosion 4.2 -Friction melts 4.3 -Bioglasses 5 -Insights into the structure and properties of glasses -ConclusionsTo date, four main groups of tektites, associated with separate impacts and strewn fields (SF), are known (e.g., [68][69][70][71]): the North American, the Ivory Coast, the central European and the Australasian (Fig. 10). The source craters have been located for three of the four tektite strewn fields, based on geographic location, geochemical evidences, and composition [72][73][74].The oldest strewn field is the North American (NA) field of ~ 35.5 Ma age associated with the ~ 40 km wide Chesapeake Bay impact structure [75] and includes Bediasites, Georgianites, Barbados and Cuba tektites, respectively found in Texas, Georgia, Barbados and Cuba (Fig. 10). The central European (CE) or moldavite strewn field of 14.4 Ma age is associated with the Ries crater of about 24km in diameter (Nördlinger Ries, Bavaria, D).There is another impact crater, the Steinheim crater, ~ 3.8 km in diameter, located about 42 kilometers west-southwest from the centre of Ries. These two craters are believed to have formed nearly simultaneously by the impact of a binary asteroid [76]. The Ivory Coast (IC) tektite strewn field is associated with the 1.07 Ma old Bosumtwi crater (10.5 km diameter, Ghana, Africa). The youngest SF, of about 0.8 Ma, is the Australasian one, for which no source crater has been identified so far. Tektites of the Australasian strewn field (AA) include australites, thailandites, indochinites, philippinites and javanites and spread from the southeastern region of Asia down to Australia (Fig. 10). Recently, glass spherules (microtektites) were discovered on the Victoria Land Transantarctic Mountains (Antarctica) and there is clear evidence [69,77,78] that these microtektites represent a major southeastward extension of the Australasian strewn field.Even if no source crater has been discovered yet, several authors suggest a location for the AA crater in the Indochina region (see [79][80][81][82]).