SOME STUDIES OF THE OPTICAL-PROPERTIES OF MOLYBDENUM PHOSPHATE-GLASSES

A series of binary MoO3-P2O5 and ternary MoO3-In2O3-P2O5 glasses was prepared and their optical properties were investigated. The optical absorption edge of the glasses was measured for specimens in the form of thin blown films. It was found that the fundamental absorption edge of these glasses usually occurs in the ultraviolet region. The linear variation of (alpha-h-omega)1/2 with h-omega where alpha is the absorption coefficient and h-omega is the incident photon energy, is taken as evidence of non-direct interband transitions. The linear dependence of optical gap with molybdenum content indicates that the molybdenum content controls the absorption phenomena in this glassy system. The infrared spectra of all the glasses appeared to be almost the same, indicating that the infrared bands arise primarily from the vibrations of the phosphate and molybdate groups. The structure of molybdenum phosphate glasses is discussed in terms of the formation of mixed phosphate and MoO4 tetrahedra.