Ads
related to: difference between photochromic and transitionswarbyparker.com has been visited by 100K+ users in the past month
Search results
Results From The WOW.Com Content Network
All photochromic molecules back-isomerize to their more stable form at some rate, and this back-isomerization is accelerated by heating. There is therefore a close relationship between photochromic and thermochromic compounds. The timescale of thermal back-isomerization is important for applications, and may be molecularly engineered.
A photochromic eyeglass lens, part of the lens darkened after exposure to sunlight while the other part remained covered. A photochromic lens is an optical lens that darkens on exposure to light of sufficiently high frequency, most commonly ultraviolet (UV) radiation. In the absence of activating light, the lenses return to their clear state.
Entropy difference between crystal and undercooled melt. As a liquid is supercooled, the difference in entropy between the liquid and solid phase decreases. By extrapolating the heat capacity of the supercooled liquid below its glass transition temperature, it is possible to calculate the temperature at which the difference in entropies becomes ...
Thermochromic and photochromic are classified as ... Transition times and light transmissivity vary by manufacturer. ... When there is a potential difference between ...
Two major classes are trans-cis (or 'E-'Z) conversion, and open-closed ring transition. Examples of the former include stilbene and azobenzene . This type of compounds has a double bond , and rotation or inversion around the double bond affords isomerization between the two states.
However, it was in the middle twenties when Fisher and Hirshbergin observed their photochromic characteristics and reversible reaction. In 1952, Fisher and co-workers announced for the first time photochromism in spiropyrans. Since then, there have been many studies on photochromic compounds that have continued up to the present. [2] [3] [4] [5]