By means of IR

Raman

x-ray

RTEM and DTA

the fundamental properties and structure of glass in the Al(PO

3

)

3

-NaBF

4

AlF

3

system have been investigated. The phase separation mechanism and relations between the phase separation and crystallization have been obtained. The experimental results indicate that glass of this system shows metaphosphate glass strueture in high phosphate content region. The structure will gradually change from meta phosphate to phyrophosphate as the aluminium metaphosphate content decreases.The phase separation mechanism of the system is nucleation and growth mechanism. The growth rule of phase dispersed paticles obyes to the diffusion—controlled mechanism. The phase separation results in complet crystallization