Laser marking involving a color change process is basically an electrical process, which rearranges the macromolecules (by changing the direction). In this case, the material “dilates” by partially expanding. It is not removed or eliminated. The “pigment” elements in the base material always contain metal ions. Laser radiation changes the crystalline structure of the ions and the level of hydration in the crystals. Consequently, the composition of the element itself undergoes a chemical transformation, causing a color change due to the greater intensity of the pigment.
Unlike the previous processes , the laser frequency is at maximum. Each pulse has a reduced energy. This is to avoid excessive expansion of the material or the removal of part of the surface.
All plastic polymers can undergo this color change process . In most of the cases, the color change is towards a darker color; a light effect is rarely obtained.