Glazing is what happens when the bonding material of the grinding wheel melts and covers the diamond particles. When this happens, the grinding wheel becomes inefficient or completely incapable of material removal. Glazing can be prevented by regulating heat during operation. There are several means of heat regulation.
One is the use of the right speed settings. Due to the differences in which grinding wheels are manufactured, different brands of grinding wheels can behave differently in terms of heat generation. Follow the right speed settings for use on specific work piece materials as per instruction of the manufacturer.