Luminescence methods for study of phase separation and crystallization in glasses

Phosphotungstate glasses doped by varying quantities of Eu³⁺ have been prepared. Depending on the relative concentration of the component and cooling rate, glassy phase or an ordered structure was obtained. The nature of the surrounding medium was determined by site selective excitation of Eu³⁺ probe ions. Striking dependence on the nature of the site was observed in a series of spectroscopic phenomena, for example: line shape of the ⁵D₀→⁷F₁ transition of Eu³⁺.