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Structure and properties of GeO2 modified borophosphate glasses
Autoři: Vorokhta Maryna | Mošner Petr | Koudelka Ladislav
Rok: 2015
Druh publikace: článek v odborném periodiku
Název zdroje: Advanced Science, Engineering and Medicine
Název nakladatele: American Scientific Publishers
Místo vydání: Valencia
Strana od-do: 331–335
Tituly:
Jazyk Název Abstrakt Klíčová slova
cze Struktura a vlastnosti borofosforečnanových skel modifikovaných GeO2 Práce je zaměřena na studium struktury, vlastností a termického chování borofosforečnanových skel připravených v kompoziční řadě (100-x)[0.4Li2O-0.4B2O3-0.2P2O5]-xGeO2 (x = 0-30 mol%). borofosforečnanová skla; struktura; vlastnosti; NMR; Ramanova spektroskopie
eng Structure and properties of GeO2 modified borophosphate glasses Structure, physico-chemical properties and thermal behaviour of GeO2-containing lithium borophosphate glasses in the compositional series (100-x)[0.4Li2O-0.4B2O3-0.2P2O5]-xGeO2 (x = 0-30 mol%) were investigated. According to the Raman spectra and 11B MAS NMR spectra, the glass structure consists mostly of BO4 tetrahedra and planar BO3 triangles. P2O5 is incorporated in the structural network mostly in the form of tetrahedral PO4 metaphosphate (Q2) and diphosphate (Q1) units. The ratio of BO4/BO3 and Q2/Q1 structural units remains practically constant with increasing GeO2 content. This suggests that GeO2 formed mainly isolated GeOx units in the structural network. The incorporation of GeO2 the glass structure results only in a small changes of physico-chemical properties. Glass transition temperature, dilatometric softening temperature and chemical durability reveal a maximum, whereas molar volume and thermal expansion coefficient reveal a minimum at the glass with 15 mol% GeO2. DTA studies showed that all of glasses crystallize on heating within the temperature region of  540-560°C. The highest thermal stability towards crystallization possesses the glass containing 10 mol% GeO2. Compounds formed by crystallization were Li3PO4 and B2O3. Borophosphate Glasses; Structure; Properties; NMR; Raman Spectroscopy