The relationship of the size of silver halide crystallites with heat treatment temperature has been studied by means of small-angle X-ray scattering (SAXS). Similar to original glass, an obvious scatter was found in glass treated bolow 490?. The behaviour of interference can be seen in the glass with only 0.3 wt. % Ag. It may be suggested that the ions of silver are concentrated in the microheterogeneous drops of the phase dispersive Na2O-B2O3. The particle size of silver halide in treated glass which cooled from higher temperature to 440 ℃ and maintained for some time and then quenched to ambient temperature was largor than that in the glass directly cooled to ambient temperature which was only a/bout 11.0 nm. By introducing ZrO2 into the glass the particle SiZe reached to near 20.0 nm. The liquid-liquid phase separation In the matrix glass was rcore difficult to determine quantitatively by SAXS because the ditiorence of the eleotron density between the dispersive and continuous phase is too small.