Binary Rare-Earth Borate Glasses

Glasses in the series R sub 2 O sub 3-B sub 2 O sub 3 and La sub 2 O sub 3-R sub 2 O sub 3-B sub 2 O sub 3, where R sub 2 O sub 3 is a 'Rare Earth' or 'Lanthanoid' oxide were prepared by bulk melting techniques. The extent of the glass forming region has been explored for each Rare Earth. Optical and physical properties have been measured with a view to establishing the structural role of the Rare Earth ions in the glasses.