| The Cu20(gla118)-Cu(glass) equilibrium was studied
in 25Na20, 10Al20 8, 65820 8 glass at varied partial
pressures of oxygen (p02 =10-11 to I0-17 atmosphere)
and temperatures in contact with solid metallic copper.
On beat-treatment, tbe best ruby was formed in glass
melted at p01=lo-14 atmosphere, at bigber p02s no
ruby colour developed, and at p02 ~I0-15 atmosphere
tbe gla!IS produced progressively poorer rubies. Using
the thermodynamic data estimated for tbe Cu20(glass)Cu(
glass) system, possibilities for tbe precipitation of
Cu (!IOlid) and Cu20 (solid) are discussed. It is concluded
that Cu20 (solid) is primarily responsible for
tbe bright red ruby colour in this glass. |
