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The series of V-doped glasses with Li20-2B203 (Li2B407). 1I2(Li20-K20-4B203). (LiKB�07). CaO-2B203 (CaB�07) and 1I2(Li20-2CaO-B203) (LiCaBO) composition containing 0.5 and 1.0 mol. % V20j oxide were obtained by standard glass technology. The electron paramagnetic resonance (EP R) and optical absorption spectra of the obtained glasses were investigated at T = 300 K The spin Hamiltonian parameters for observed EPR spectra in the Li2B407: V. LiKB407: V. CaB407: V and LiCaB03: V glasses were determined and electron and local structure of impurity V centres were proposed. The optical absorption bands. observed in the investigated glasses have been interpreted. During last decades considerable interest appears for study of glasses activated with transitional metal ions as promising functional materials, including V-doped borate glasses. The electron paramagnetic resonance (EPR) and optical spectroscopy are powerful methods for study of the electron and local structure of the activator centres in crystals and glasses. Vanadium has been widely investigated in a variety of host systems, as V 4 + (3 d\ 2 D3/Z) ion and more often as stable oxo-vanadium molecular ion (V0 2 + or vanadyl) [1]. The V 4 + ions usually are located in tetrahedral coordination and are characterised by short spin-lattice relaxation time (T]), therefore their EPR spectra can only be observed at T"Sc 77 K. The V0 2 + centres usually are located in a pyramidal or distorted octahedral coordination and have a long TI, so their EPR spectra can be observed at room temperature (RT) [1]. At present time EPR and optical absorption spectra were investigated in V-doped Li 2 B407 [2], SrB407 [3] and alkali calcium borate glasses [4], whereas in the V-doped lORzO2SPbO-62B 2 03 (R = Li, Na, K) glasses the EPR spectra were investigated [S]. Tn this work the EPR and optical absorption spectra in the series of glasses with Li 2 B407:V, LiKB407:V, CaB407:V and LiCaB03:V compositions have been studied. 11. EXPERIMENTAL DETAILS The V -doped borate glasses of high optical quality and chemical purity with Li 2 B407, LiKB407, CaB407 and LiCaB03 basic chemical compositions were obtained using corresponding polycrystalline compounds by standard glass synthesis according to technological set-up, described in [6]. Carbonates (CaC03, Li1C03, K 2 C03) and boric acid (H3B03) of high chemical purity were used for synthesis of Li 2 B407, LiKB407, CaB407 and LiCaB03 polycrystalline compounds. The V impurity was added to the raw materials as V10 S in amounts O.S and l.0 mol. %. Solid-state synthesis of the borate compounds were carried out using multi-step heating process [6]. The LizB407:V, LiKB407:V, CaB407:V and LiCaB03:V glasses of high optical quality were obtained by fast cooling of melts, heated more than 100 K higher that melting temperatures for excluding crystallisation processes.The X-band EPR spectra of V-doped borate glasses were registered at RT using a RADIOPAN spectrometer (model SEIX-2013). Optical absorption spectra were recorded at RT using a Varian spectrophotomet...

Abstract. We have investigated the optical properties (optical absorption, photoluminescence emission and excitation spectra, and luminescence kinetics) of a series of Eu-doped

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