UVsárgulás

UVsárgulás, also known as UV-induced yellowing or photo-yellowing, is a chemical process that occurs when certain materials, particularly organic compounds, are exposed to ultraviolet (UV) light. This phenomenon is commonly observed in plastics, paper, and other materials that contain chromophores, which are molecules that absorb light and can undergo chemical changes when exposed to UV radiation.

The process begins when UV light, typically in the range of 300-400 nanometers, is absorbed by the chromophores in the material. This absorption excites the electrons in the chromophores, causing them to jump to a higher energy level. When the electrons return to their original energy level, they release energy in the form of heat or light, but in some cases, they may also cause chemical bonds within the material to break and reform, leading to the formation of new chromophores.

These new chromophores often absorb visible light in the yellow or orange part of the spectrum, which is why UVsárgulás is characterized by a yellowing or discoloration of the material. The extent of the yellowing depends on several factors, including the intensity and duration of the UV exposure, the type of material, and its initial composition.

UVsárgulás is a significant concern in various industries, including packaging, textiles, and art conservation, as it can degrade the appearance and quality of materials over time. To mitigate UVsárgulás, materials can be formulated with UV stabilizers, which are compounds that absorb or scatter UV light, preventing it from reaching the chromophores and initiating the yellowing process. Additionally, materials can be designed to minimize the presence of chromophores or to use chromophores that are less susceptible to UV-induced changes.