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Review on the structure of borate glasses by Raman spectroscopic technique.

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Title: Review on the structure of borate glasses by Raman spectroscopic technique.
Authors: Pavan Kumar, C.S.1 (AUTHOR), Pratap, Satwik2,3 (AUTHOR), Sumuka, C.S.2,4 (AUTHOR), Sivasankara Reddy, N.1 (AUTHOR) sivasankarareddy@presidencyuniversity.in
Source: Ceramics International. Jan2026, Vol. 52 Issue 2, p1359-1382. 24p.
Subjects: Borate glass, Raman spectroscopy, Optical properties, Structural analysis (Science), Glass structure, Oxides
Abstract: The range of technological applications for borate glasses is steadily expanding over time. Determining the structure of borate glasses with different modifiers is an area where more clarity is needed. Raman spectroscopy is the most used technique to understand the structure. Even though large amount of data is generated, there are many unanswered questions about glass network structure in borate systems. This review aims to deepen the understanding of the borate glass network by examining structural modifications induced by various modifier oxides, including alkali, alkaline earth, and transition metal oxides, as reported in recent literature. This review also provides a comprehensive analysis of how various modifiers and formers alter their short- and medium-range order. Raman spectra capture characteristic vibrations of key borate units, each sensitive to compositional changes. Modifier oxides like ZnO, MgO, PbO, Te O 2 , and rare-earth oxides systematically disrupt boroxol rings, favouring the formation of pyroborates, metaborates, and orthoborates. For example, when ZnO is added to a borate glass, the Zn2+ ions can act as network formers by adopting a tetrahedral coordination (ZnO 4). But they also break some of the B–O–B bridges depolymerizing and opening the borate rings. This increases NBOs and thereby modifying the glass structure. On the other hand, in tellurium borate glasses Te O 2 transform from Te O 4 to Te O 3 when other oxides are added. These TeO 3 units often share oxygen atoms with borate groups creating complex Te–O–B linkages. Similarly, in PbO containing glasses, Pb2+ ions act as network modifiers at low concentrations, breaking B–O–B bridges and creating NBOs. However, as PbO content increases, lead begins to behave as a network former, forming PbO 4 tetrahedral units. Investigations into alkali borosilicate and borogermanate glasses reveal how substituting cations or incorporating B 2 O 3 reshapes Q-species distributions or triggers the "germanate anomaly," while gadolinium borate glasses transition from complex borate networks to simpler B O 3 -dominated structures with increasing G d 2 O 3. Overall, Raman spectroscopy emerges as a powerful probe to decode these structural rearrangements, offering insights for designing glasses with tailored optical, mechanical, and thermal properties. [ABSTRACT FROM AUTHOR]
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Database: Engineering Source
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Abstract:The range of technological applications for borate glasses is steadily expanding over time. Determining the structure of borate glasses with different modifiers is an area where more clarity is needed. Raman spectroscopy is the most used technique to understand the structure. Even though large amount of data is generated, there are many unanswered questions about glass network structure in borate systems. This review aims to deepen the understanding of the borate glass network by examining structural modifications induced by various modifier oxides, including alkali, alkaline earth, and transition metal oxides, as reported in recent literature. This review also provides a comprehensive analysis of how various modifiers and formers alter their short- and medium-range order. Raman spectra capture characteristic vibrations of key borate units, each sensitive to compositional changes. Modifier oxides like ZnO, MgO, PbO, Te O 2 , and rare-earth oxides systematically disrupt boroxol rings, favouring the formation of pyroborates, metaborates, and orthoborates. For example, when ZnO is added to a borate glass, the Zn2+ ions can act as network formers by adopting a tetrahedral coordination (ZnO 4). But they also break some of the B–O–B bridges depolymerizing and opening the borate rings. This increases NBOs and thereby modifying the glass structure. On the other hand, in tellurium borate glasses Te O 2 transform from Te O 4 to Te O 3 when other oxides are added. These TeO 3 units often share oxygen atoms with borate groups creating complex Te–O–B linkages. Similarly, in PbO containing glasses, Pb2+ ions act as network modifiers at low concentrations, breaking B–O–B bridges and creating NBOs. However, as PbO content increases, lead begins to behave as a network former, forming PbO 4 tetrahedral units. Investigations into alkali borosilicate and borogermanate glasses reveal how substituting cations or incorporating B 2 O 3 reshapes Q-species distributions or triggers the "germanate anomaly," while gadolinium borate glasses transition from complex borate networks to simpler B O 3 -dominated structures with increasing G d 2 O 3. Overall, Raman spectroscopy emerges as a powerful probe to decode these structural rearrangements, offering insights for designing glasses with tailored optical, mechanical, and thermal properties. [ABSTRACT FROM AUTHOR]
ISSN:02728842
DOI:10.1016/j.ceramint.2025.12.004