Method for separating substrates

A workpiece comprising:

• a glass product, glass ceramic product, or silicon product that has been pre-damaged along a separation line with defects at a spacing from one another along the separation line;
• a breaking stress (σB) along the separation line is smaller than a first reference stress (σR1) of the glass product, glass ceramic product, or silicon product;
• and
• an edge strength (σK) of a separation edge obtained after separation at the separation line that is greater than a second reference stress (σR2) of the glass product, glass ceramic product, or silicon product,
• wherein the first reference stress (σR1) and the second reference stress (σR2) are equal and are a maximum thermal stress (σth) of the glass product, glass ceramic product, or silicon product,
• wherein the maximum thermal stress (σth) is defined according to a formula σth=0.5·α·E·(Tg−100° C.),
• wherein α is a coefficient of thermal expansion of the glass product, glass ceramic product, or silicon product,
• wherein E is a Young's modulus of the glass product, glass ceramic product, or silicon product, and
• wherein Tg is a glass transition temperature of the glass product, glass ceramic product, or silicon product.