Ref: http://physicsweb.org/article/news/8/8/9

Scientists in the US have developed a novel
technique to make bulk quantities of glass from
alumina for the first time. Anatoly Rosenflanz and
colleagues at 3M in Minnesota used a "flame-spray"
technique to alloy alumina (aluminium oxide) with
rare-earth metal oxides to produce strong glass
with good optical properties. The method avoids
many of the problems encountered in conventional
glass forming and could, say the team, be extended
to other oxides (A Rosenflanz et al. 2004 Nature
430 761).

Glass is formed when a molten material is cooled
so quickly that its constituent atoms do not have
time to align themselves into an ordered lattice.
However, it is difficult to make glasses from most
materials because they need to be cooled -- or
quenched -- at rates of up to 10 million degrees
per second.

See: http://physicsweb.org/article/news/8/8/9