Glass mold generally divided into five phases: 1 on the surface of water or moisture adsorbed on the glass. 2 water or moisture to the glass internal diffusion. Soluble silicate glass surface in 3 destroyed by hydrolysis. 4 isolated SiO2 generation silica gel, the formation of a protective film on the glass surface, it prevented further erosion. The 5 formed by hydrolysis of caustic soda, and carbon dioxide in the air of the effect of sodium carbonate formation, gathered in the glass surface, constitutes the soluble salt in the surface film. Because of its strong hygroscopic, moisture absorption and deliquescence, finally forming droplets lye. When the temperature, humidity changes around, these little drops of concentration changes. If the concentration of the droplets lye and glass long-term contact, gelatinous silica films can be dissolved in some way, and make the glass surface has a local erosion is serious, the formation of spots. This is the sodium ion transport out of the glass body, generating reaction with air white alkali ion group. Scanning electron microscope can be observed in white particle swarm.