Εξειδίκευση τύπου :	Άρθρο σε επιστημονικό περιοδικό
Τίτλος:	Borate glass structure by vibrational spectroscopy: a review on borate speciation and metal ion-site interactions
Δημιουργός/Συγγραφέας:	[EL] Καμίτσος, Ευστράτιος Ι.[EN] Kamitsos, Efstratios I.
Εκδότης:	Society of Glass Technology
Ημερομηνία:	2025
Γλώσσα:	Αγγλικά
DOI:	10.13036/17533562.66.1.01
Περίληψη:	This article reviews our work on the structure of borate glasses conducted at the National Hellenic Research Foundation since 1985, in collaboration with numerous colleagues around the world. Both infrared and Raman spectroscopies were employed to study the borate structure, because these techniques provide complementary information due to differences in selection rules. Borate glasses containing modifier metal ions such as alkali, alkaline earth, rare earth, transition and post-transition metal ions,were prepared and studied to probe the evolution of the borate speciation with composition. B2O3 glass consists of neutral, planar [BØ3]0 triangles where Ø is bridging oxygen, with ca.75% of them being arranged in planar hexagonal boroxol rings. At low metal oxide contents the [BØ3]0 species transform to negatively charged [BØ4]– metaborate tetrahedra. The change in boron coordination is widely accepted as the basis of distinct differences in the composition dependence of properties between silicate and borate glasses. The latter exhibit non-monotonic variations in physical properties with metal oxide content, known as the borate anomaly. At higher modifier oxide contents, non-bridging oxygen atoms (O) are formed on metaborate triangles, [BØ2O]–,and pyroborate species, [BØO2]2–, until finally orthoborate monomers, [BO3]3–, are generated and lead to the complete depolymerisation of the borate network. In highly modified glasses (invert glasses) the [BO3]3– triangles may exist in equilibrium with isomeric orthoborate tetrahedra, [BØ2O2]3–, the formation of which partially re-establishes the borate connectivity and leads to a second manifestation of the borate anomaly. It was discussed that the chemical reactions and equilibria between borate species are controlled by composition, the field strength of the modifier cation, the temperature and pressure, and the external dc electric field for electro-thermal poling. Change in borate speciation directly affects the complex environments (sites) of the metal ions in the glass matrix. This has important implications for physical properties like ionic transport and glass basicity, as these properties depend directly on the nature and spatial distribution of the sites hosting the modifier metal ions. In this context, far-infrared spectroscopy has been employed to probe metal ion–site interactions in glasses and the results are discussed in relation to those of molecular dynamics simulations on single and mixed alkali borate glasses.
Τίτλος πηγής δημοσίευσης:	Physics and Chemistry of Glasses - European Journal of Glass Science and Technology Part B
Τόμος/Κεφάλαιο:	66
Τεύχος:	1
Θεματική Κατηγορία:	[EL] Φυσική και θεωρητική χημεία[EN] Physical and theoretical chemistry [EL] Φασματοσκοπία[EN] Spectroscopy
Λέξεις-Κλειδιά:	borate glass structure vibrational spectroscopy borate anomaly metal ion-site interactions
Ηλεκτρονική διεύθυνση στον εκδότη (link):	https://doi.org/10.13036/17533562.66.1.01
Εμφανίζεται στις συλλογές:	Ινστιτούτο Θεωρητικής και Φυσικής Χημείας (ΙΘΦΧ) - Επιστημονικό έργο