Method for modifying a vitreous material

A method of treating a vitreous material comprising the following steps:

• i. providing
• a. a piece of vitreous material;
• wherein said piece of vitreous material comprises at least two opposite faces;
• and
• b. at least one laser beam source;
• ii. heating the piece of vitreous material of step (i) at a temperature comprised between 400 and 640° C.;
• iii. applying at least one laser beam with the at least one laser beam source of step (i) on at least one of the faces of the piece of vitreous material of step (ii), performing a scan following a line surpassing the opposite edges of the at least one of the faces of the piece of vitreous material;
• while the piece of vitreous material moves following a path forming an angle of between 30 and 120° with the scan line of the laser beam;
• wherein said scan is performed while the piece of vitreous material is at a temperature comprised between 400° C. and 640° C.;
• iv. heating the piece of vitreous material obtained in step (iii) at a temperature comprised between 450° C. and 650° C.;
• and
• v. cooling the piece of vitreous material of step (iv);
• wherein the laser beam and the at least one of the faces of the piece of vitreous material form an angle of between 15 and 90°;
• wherein the laser beam is focused on a point of the face of the piece of material, wherein the scan follows a line surpassing the opposite edges of the face of the piece of vitreous material of step (iii), said scan being performed in a direction from a first point to a second point;
• once said laser beam reaches the second point, the laser beam performs the same scan but in the opposite direction until reaching the first point;
• wherein the scan is performed by oscillating movement following a straight line surpassing the two opposite edges of the face of the piece of vitreous material.