Browsing by Author "Khanna A."

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    Eu3+ doped glasses in the Bi2O3-B2O3-WO3-Al2O3 system
    (2015-01-01) Aleksandrov L.; Iordanova R.; Khanna A.; Georgiev N.; Dimitriev Y.
    The structure of many Eu3+ doped Bi2O3-B2O3-WO3-Al2O3 glasses of a different composition is studied using infrared spectroscopic technique (IR). It is found that distorted BiO6 (of a band at 480 cm-1), BO3 (of bands at 1390, 1230, 620 cm-1), BO4 (of a band at 1020 cm-1) and WO4 polyhedra (of a band at 880 cm-1) are the main building units forming the amorphous networks. WO6 groups exist in the glass network of a high WO3 content (of bands at 880 cm-1, 620 cm-1, and a shoulder at 670 cm-1). WO3 does not stimulate formation of BO4 structural units. According to the differential thermal analysis (DTA) the glass transition temperature (Tg) of the investigated glasses is situated in the range of 400°C - 485°C. The DTA curves of all glasses show two exothermic peaks corresponding to the formation of two crystal phases. Photoluminescence emissions due to the 4f transitions 5D0→7Fj (j=0-4) of Eu3+ ions are observed. The addition of WO3 to the glass compositions decreases the emission intensity of investigated glasses.