Study of optical absorption edges in MgO-P2O5 glasses
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A series of glass specimens were prepared from the binary glasses (MgO-P2O5) and their densities and optical absorption edges in the ultraviolet-visible ranges were measured. It was found that the fundamental absorption edge is a function of glass composition and at lower values of the absorption coefficients α(ω) it follows the so-called Urbach edge. From this edge the value ofEe, the width of the tail of localized states in the bandgap, did not vary significantly with glass composition. In the higher energy region, the behaviour of α(ω) suggests that there are two different transition energies for electrons, namely direct allowed transitions and non-direct transitions ink space. From these results some information about the band structure of MgO-P2O5 glass is presented.
KeywordsPolymer Absorption Coefficient Localize State Band Structure Optical Absorption
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