Method of producing glass-ceramic

A method of producing glass-ceramic, comprising:

• providing a glass made from a glass composition comprising LiO2, Al2O3, SiO2, and at least one nucleating agent;
• disposing the glass in a microwave processing chamber;
• selectively delivering microwaves into the microwave processing chamber at varying frequencies in a range from 5.4 GHz to 7.0 GHz to induce different distributions of microwave fields in the glass;
• heating the glass to a nucleation temperature under the influence of the induced microwave fields;
• maintaining the glass at the nucleation temperature under the influence of the induced microwave fields for a time period during which crystal nuclei develop in the glass;
• heating the glass to a crystallization temperature under the influence of the induced microwave fields;
• maintaining the glass at the crystallization temperature under the influence of the induced microwave fields for a time period during which at least one crystalline phase grows in the glass, thereby forming a glass-ceramic;
• and
• cooling the glass-ceramic from the crystallization temperature to room temperature, the cooling comprising an initial phase in which microwaves are applied to the glass-ceramic, wherein a temperature of the glass-ceramic drops by 5% to 20% of the crystallization temperature during the initial phase of the cooling.