What is the Difference Between Photochromic and Thermochromic?

The main difference between photochromic and thermochromic materials lies in the stimuli that cause them to change color. Here are the key differences:

• Photochromic materials:
• Darken upon exposure to ultraviolet (UV) or visible light.
• Made mainly from glass, polycarbonate material, and plastics.
• Primarily used in the context of lenses for eyewear.
• Thermochromic materials:
• Change color upon changes in temperature.
• Can be either natural or synthetic materials.
• Often used in a wide range of applications, such as mood rings, thermochromic inks, and temperature-sensitive paints.

Both photochromic and thermochromic materials can operate reversibly and are considered passive technologies, meaning they do not require an external power source to function. However, photochromic materials respond to light, while thermochromic materials respond to heat.

Comparative Table: Photochromic vs Thermochromic

While photochromic and thermochromic materials both exhibit reversible color changes, they respond to different stimuli. Here is a table summarizing their differences:

Photochromic materials darken upon exposure to UV radiation, while thermochromic materials change their color upon changes in temperature. Both materials can revert to their original state, making them suitable for various applications. The terms photochromic and thermochromic are mainly used in the context of lenses, where colors change in response to UV radiation or temperature.