Studies of oxynitride glasses have been encouraged by the interesting
changes in physical properties, such as hardness and refractive index,
observed when nitrogen is incorporated in glasses. However, despite a
ttempts involving many combinations of different cations, only one of
four oxygen atoms has been successfully replaced by nitrogen in phosph
ate and silicate systems. In the present paper, glass formation in Li3
N-Ca3N2-P3N5 is reported. Some attempts to chemically substitute Ca3N2
and Li3N in these glasses are also described. The nitride glasses wer
e obtained by melt quenching in a high-pressure, high-temperature pist
on cylinder device, The high-pressure experiments oppose thermal decom
position to gaseous nitrogen which previously has limited the nitrogen
content in oxynitride glasses. The present examples of this new class
of glass have interesting properties, particularly remarkably high re
fractive index and hardness.