- #1
Thalita Luna
- 4
- 1
Photochromic lenses are common in glasses, they stay transparent indoor, but get darken when exposed to sunlight. How does it work ?
In summary, the conversation involves a person asking for help with summarizing content and being told that they do not respond to questions, but only provide summaries. The person is then given the task of summarizing the conversation itself.
- #2
berkeman
Mentor
- 68,384
- 22,241
Welcome to PF. 
Google is your friend; following links are from searches on photochromic lens and photochromic molecule:
https://www.transitions.com/en-us/why-transitions/the-technology/photochromic-tech/
https://en.wikipedia.org/wiki/Photochromism
Google is your friend; following links are from searches on photochromic lens and photochromic molecule:
https://www.transitions.com/en-us/why-transitions/the-technology/photochromic-tech/
https://en.wikipedia.org/wiki/Photochromism
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FAQ: How do Photochromic lenses work?
What are photochromic lenses?
Photochromic lenses are optical lenses that darken on exposure to specific types of light, typically ultraviolet (UV) light. When the light source is removed, the lenses gradually return to their clear state. This makes them convenient for both indoor and outdoor use as they adapt to changing light conditions.
How do photochromic lenses change color?
Photochromic lenses contain special molecules, such as silver halide or organic compounds, that undergo a chemical reaction when exposed to UV light. This reaction causes the molecules to change their structure, absorbing more light and causing the lens to darken. When the UV light is no longer present, the molecules revert to their original structure, and the lens becomes clear again.
Do photochromic lenses work indoors?
Photochromic lenses typically do not darken indoors because most indoor lighting does not emit enough UV light to trigger the chemical reaction. However, some newer photochromic lenses are designed to respond to both UV and visible light, allowing them to darken slightly indoors under certain lighting conditions.
How long does it take for photochromic lenses to change?
The time it takes for photochromic lenses to change from clear to dark and vice versa can vary depending on the specific product and environmental conditions. Generally, lenses can darken within a minute or two when exposed to UV light and return to their clear state within a few minutes after the UV light is removed. Temperature can also affect the speed of the transition; colder temperatures may slow down the process.
Are photochromic lenses suitable for driving?
Photochromic lenses may not be ideal for driving because most car windshields block a significant amount of UV light, which prevents the lenses from darkening effectively. However, some lenses are specifically designed to work with visible light as well, making them more suitable for driving. It's important to check the specifications of the lenses to ensure they meet your needs for driving.