Glass beads and uses thereof

In one aspect, the invention provides glass beads and optical devices comprising the glass beads. In other aspects, the invention provides methods of making said glass beads and rapid glass screening methods that use glass beads. Glass beads of the invention comprise greater than 80 weight percent silica, active rare earth dopant, and modifying dopant. In another embodiment the glass beads comprise greater than 80 weight percent silica and at least 5 weight percent germania. In another embodiment, glass beads comprise and from about 20 to about 90 anion mole percent of non-oxide anion.