Transparent β-quartz glass-ceramics with low lithium content

A method of preparing an article constituted, at least in part, of a glass-ceramic containing a solid solution of β-quartz as its main crystalline phase, comprising in succession:

• melting a charge of raw materials able to vitrify, followed by fining the resulting molten glass;
• cooling the resulting fined molten glass and simultaneously shaping it to the shape desired for the intended article;
• and
• applying ceramming heat treatment to said shaped glass;
• wherein said charge has a composition that makes it possible to obtain the transparent glass-ceramic, the composition of which, free of arsenic oxide and antimony oxide, except for inevitable traces, expressed as percentages by weight of oxides, comprises:
• 62% to 68% of SiO2;
• 17% to 21% of Al2O3;
• 1% to <2% of Li2O;
• 1% to 4% of MgO;
• 1% to 6% of ZnO;
• 0 to 4% of BaO;
• 0 to 4% of SrO;
• 0 to 1% of CaO;
• 1% to 5% of TiO2;
• 0 to 2% of ZrO2;
• 0 to 1% of Na2O;
• 0 to 1% of K2O;
• with Na2O+K2O+BaO+SrO+CaO≤6%;
• 0 to 2% of at least one fining agent comprising SnO2;
• and
• 0.01% to 2% of at least one coloring agent, wherein the coloring agent comprises 0.005% to 0.1% V2O5 mixed with at least one other coloring agent selected from CoO, Cr2O3, and Fe2O3,
• wherein the transparent glass ceramic comprises a coefficient of thermal expansion CTE25° C.-300° C. of less than 20·10−7K−1,
• the transparent glass ceramic having a thickness from 1 mm to 8 mm and an integrated transmission of less than 10% while maintaining transmission at 625 nm greater than 1% and at 950 nm from 50% to 75%.