1 mol %) were prepared by melt quenching are studied. Spectroscopic (XRD, infrared, optical absorption spectra and EPR) properties of these glasses have been carried out. As the concentration of MoO 3 is increased especially beyond 0.4 mol %, the colour of the glasses increased, which is indicating the reduction of molybdenum ions from …………………………………………………………………………………………………….... Introduction:-The glasses containing transition metal ions came into prominence because of their notable spectroscopic properties and their suitability for fibre optic communications, luminescent solar energy concentrators (LSC) [1].Among the many glasses, borate glasses have been known to be excellent host materials for transition metal oxides because of their glass forming nature compared to other conventional glass systems. Borate glasses are used as wave-guides, electro-optic switches, electro-optic modulators, magneto-optic materials, solid-state laser materials and non-linear optical parametric converters [2][3][4]. In addition, they are often used as dielectric and insulating materials and it is known that borate glass constitute a good shield against IR radiation [5]. In general B 2 O 3 glasses have a property of showing minimum expansion due to the large amount of boric oxide which is of great importance in obtaining thermal durability. It also decreases the tendency for glass to devitrify or crystallize. B 2 O 3 is a basic glass former because of its higher bond strength, lower cation size and smaller heat of fusion. The ions of molybdenum introduce high activity and selectivity in a series of oxidation reactions of practical importance in the glass matrices [6,7].Molybdenum oxide belongs to the intermediate class of glass forming oxides. It does not readily form the glass but does so in the presence of the modifier with MoO 4 . Molybdenum ions in the glasses have been the subject of many investigations due to their catalytic properties. Interesting studies are available on the environment of molybdenum ion in different inorganic glasses [8][9][10][11][12][13]. Mo-O bond in molybdenum hexavalent oxide is identified as significantly covalent. The Mo ion exist a stable valence state viz., MoV and MoVI in the glass network. Molybdenum ions act both as network formers as well as network modifiers depending upon their concentration and nature of the host network.Mo−O bond in molybdenum hexavalent oxide is identified as covalent. The Mo ion exists at least in two