CR4 - The Engineer's Place for News and Discussion ®


Previous in Forum: Carbon Buildup in Toyota Hybrid EGR Exhaust Baffle   Next in Forum: ASTM G48
Close
Close
Close
29 comments
Guru

Join Date: Oct 2006
Location: 44.56024"N 15.307971E
Posts: 3186
Good Answers: 153

Reversible Color Change

05/20/2016 6:07 AM

Does anyone know of a substance that will change color by application of a certain frequency of light,then revert back to the original color when another frequency is applied?

I have googled but perhaps I am not asking the right questions.

Thanks in advance for any and all help on this.

__________________
"A man never stands so tall as when he stoops to help a child." “I've learned that people will forget what you said, people will forget what you did, but people will never forget how you made them feel.” Maya Angelou.
Register to Reply
Interested in this topic? By joining CR4 you can "subscribe" to
this discussion and receive notification when new comments are added.
Guru
Engineering Fields - Mechanical Engineering - New Member Fans of Old Computers - TRS-80 - New Member Popular Science - Weaponology - New Member Safety - Hazmat - New Member Hobbies - Fishing - New Member United States - Member - New Member

Join Date: Apr 2012
Location: Detroit MI, USA
Posts: 2032
Good Answers: 204
#1

Re: Reversible color change

05/20/2016 6:45 AM
__________________
How we deal with death is at least as important as how we deal with life. --CAPTAIN KIRK, Star Trek II: The Wrath of Khan
Register to Reply
Guru
Engineering Fields - Mechanical Engineering - New Member Fans of Old Computers - TRS-80 - New Member Popular Science - Weaponology - New Member Safety - Hazmat - New Member Hobbies - Fishing - New Member United States - Member - New Member

Join Date: Apr 2012
Location: Detroit MI, USA
Posts: 2032
Good Answers: 204
#2

Re: Reversible color change

05/20/2016 6:48 AM

Also, my glasses technically do that, they are Transitions.

__________________
How we deal with death is at least as important as how we deal with life. --CAPTAIN KIRK, Star Trek II: The Wrath of Khan
Register to Reply
Guru

Join Date: Oct 2008
Posts: 39624
Good Answers: 1570
#3

Re: Reversible color change

05/20/2016 8:59 AM
Register to Reply
Guru
Hobbies - CNC - New Member Hobbies - DIY Welding - New Member Engineering Fields - Electromechanical Engineering - New Member

Join Date: Aug 2007
Posts: 18712
Good Answers: 329
#19
In reply to #3

Re: Reversible color change

05/23/2016 9:04 AM

About 15 years ago I found out what that paint costs.... I wonder if it came down in price.

__________________
phoenix911
Register to Reply
Guru
United Kingdom - Member - Indeterminate Engineering Fields - Control Engineering - New Member

Join Date: Jan 2007
Location: In the bothy, 7 chains down the line from Dodman's Lane level crossing, in the nation formerly known as Great Britain, and now disconnecting as Little England and Wales (not too sure about Wales bit, either). Kettle's on.
Posts: 26621
Good Answers: 699
#4

Re: Reversible color change

05/20/2016 9:04 AM

Steel changes colour when infra-red light is poured onto it from a heat source. It goes through transition colours until it is bright red. Turn the infra-red heart source off and leave it in daylight to cool, and the red disappears.

__________________
"Did you get my e-mail?" - "The biggest problem in communication is the illusion that it has taken place" - George Bernard Shaw, 1856
Register to Reply
Guru
Safety - Hazmat - New Member United States - US - Statue of Liberty - New Member Engineering Fields - Chemical Engineering - Old Hand

Join Date: Mar 2011
Location: Lubbock, Texas
Posts: 12922
Good Answers: 147
#5

Re: Reversible color change

05/20/2016 9:32 AM

"The unimolecular processes are encountered, for example, with spiropyrans, a family of molecules that has been studied extensively. Solid photochromic spiropyrans or solutions (in ethanol, toluene, ether, ketones, esters, etc.) are colorless or weakly colored. Upon UV irradiation, they become colored. The colored solutions fade thermally to their original state; in many cases, they can also be decolorized (bleached) by visible light. A few spiropyrans display negative photochromism. They are colored in the dark and bleached by UV light. Many spiropyrans are also thermochromic (see definition below), and spectra of the colored forms are identical to those produced photochemically". quoted from this research paper on photochromism:

http://www.journalamme.org/papers_vol41/4116.pdf

Notice it mentions also the effect of photobleaching (the removal of the color formed).

Thus, I would say the answer to your question is yes. Apparently, spiropyrans exhibit this behavior in liquid solution, and also when incorporated in "solution" in such plastics at polystyrene. 3D optical memory is one potential application of this effect.

__________________
If it ain't broke, don't fix it. Just build a better one.
Register to Reply
Guru
Engineering Fields - Optical Engineering - Member Engineering Fields - Engineering Physics - Member Engineering Fields - Systems Engineering - Member

Join Date: Apr 2010
Location: Trantor
Posts: 5172
Good Answers: 614
#6

Re: Reversible Color Change

05/20/2016 4:28 PM

There are thermochromic paints that change color when heat (infrared radiation) is applied. Once they cool, they will revert back to their original color. You can buy coffee mugs and glasses that have hidden images that appear or disappear when hot or cold beverages are poured into them.

Likewise there are liquid crystal materials that change color depending on temperature. I think this is how 'mood rings' work.

There is also a phenomenon known as 'metamerism' where a material will have a different color depending on the lighting. I remember first noticing this when I was wearing a blue shirt while standing near one of those outdoor yellow 'bug lights'. The yellow light made my blue shirt look green.

There is also 'sunprint' paper that changes from dark blue to light blue / white when exposed to sunlight. (I think if you don't process it, it will revert back to dark blue.)

I've noticed that 'glow in the dark' material is affected by shining a laser pointer at it, causing the glow to extinguish more quickly.

But if you're looking for a material that can be switched quickly and repeatedly from one color to another just using light, I don't kow of a material like that.

__________________
Whiskey, women -- and astrophysics. Because sometimes a problem can't be solved with just whiskey and women.
Register to Reply
Guru

Join Date: Jan 2006
Location: Tamworth, UK.
Posts: 1528
Good Answers: 35
#7

Re: Reversible Color Change

05/21/2016 5:08 AM

Ordinary white painted surfaces change colour to match the frequency of light waves shining on it. And it goes back to the original colour when the light is removed.

This does not answer your question, but it might point you to something suitable.

__________________
When arguing, remember mud-slinging = lost ground.
Register to Reply
Guru

Join Date: Dec 2010
Location: North West England
Posts: 916
Good Answers: 114
#8

Re: Reversible Color Change

05/21/2016 5:11 AM

Mirrors are good for this. They also have light speed reaction times.

Register to Reply
Guru

Join Date: Mar 2011
Location: Sebastopol, California
Posts: 825
Good Answers: 35
#9

Re: Reversible Color Change

05/21/2016 11:39 AM

I don't know what your application is, but fluorescent pigments come to mind. They can appear one color in normal light and a different bright color in UV.

__________________
Most people are mostly good most of the time.
Register to Reply
Guru

Join Date: Mar 2007
Location: at the beach in Florida
Posts: 18917
Good Answers: 1101
#10

Re: Reversible Color Change

05/21/2016 12:27 PM

If you want it to react immediately, and have a wide range, you could build a system that detects the light frequency and reacts by sending a signal to an LED array for a specific wavelength of color and heat with tuneable LED's....

Light To Frequency & Light To Voltage

Color changing led

http://www.first-sensor.com/en/products/optical-sensors/detectors/wavelength-sensitive-diodes-ws/

__________________
Life is like riding a bicycle. To keep your balance you must keep moving. A.E.
Register to Reply
Guru

Join Date: Oct 2006
Location: 44.56024"N 15.307971E
Posts: 3186
Good Answers: 153
#11

Re: Reversible Color Change

05/21/2016 1:58 PM

Thanks for all the feedback.Many good suggestions.

Here are a little more details on what I am seeking:

The material has to respond instantly to a light source,and stay in the changed state in the absence of light until reversed by a different frequency,and be able to switch states without limitation on the number of cycles.

I realize this is a pie-in-the sky wish list,but those are the requirements I seek.

Hopefully it wont turn into a pie-in-the face wish list.

__________________
"A man never stands so tall as when he stoops to help a child." “I've learned that people will forget what you said, people will forget what you did, but people will never forget how you made them feel.” Maya Angelou.
Register to Reply
Guru

Join Date: Sep 2008
Location: Where the sun sets on OZ
Posts: 1314
Good Answers: 27
#13
In reply to #11

Re: Reversible Color Change

05/22/2016 1:14 AM

You want it to change colour when lit and remain that colour in the dark? How would you know? See Schrodingers cat!!

Jim

__________________
Where's the KaBoom? There should be a KaBoom!
Register to Reply
Guru

Join Date: Mar 2007
Location: at the beach in Florida
Posts: 18917
Good Answers: 1101
#12

Re: Reversible Color Change

05/21/2016 4:45 PM
__________________
Life is like riding a bicycle. To keep your balance you must keep moving. A.E.
Register to Reply
Guru

Join Date: Oct 2006
Location: 44.56024"N 15.307971E
Posts: 3186
Good Answers: 153
#14
In reply to #12

Re: Reversible Color Change

05/22/2016 7:18 AM

Very interesting!I wonder how fast this transition occurs?

I am thinking 3D memory device,so it must happen very quickly.

__________________
"A man never stands so tall as when he stoops to help a child." “I've learned that people will forget what you said, people will forget what you did, but people will never forget how you made them feel.” Maya Angelou.
Register to Reply
Guru
Safety - Hazmat - New Member United States - US - Statue of Liberty - New Member Engineering Fields - Chemical Engineering - Old Hand

Join Date: Mar 2011
Location: Lubbock, Texas
Posts: 12922
Good Answers: 147
#17
In reply to #14

Re: Reversible Color Change

05/23/2016 8:24 AM

Look at the azobenzene chemistry lesson again. This stimulated absorption of light happens faster than ein eugenblick.

As to switching back to the trans isomer from the cis isomer, not sure. Photochromic switches already exist.

__________________
If it ain't broke, don't fix it. Just build a better one.
Register to Reply
Guru
Hobbies - CNC - New Member Hobbies - DIY Welding - New Member Engineering Fields - Electromechanical Engineering - New Member

Join Date: Aug 2007
Posts: 18712
Good Answers: 329
#15

Re: Reversible Color Change

05/22/2016 3:45 PM

I beleive how Chromatic color changes, if it's just the angle of light.

https://en.m.wikipedia.org/wiki/ChromaFlair

I don't know about frequency.

__________________
phoenix911
Register to Reply
Guru
Popular Science - Weaponology - New Member United Kingdom - Member - New Member

Join Date: May 2007
Location: Harlow England
Posts: 16257
Good Answers: 624
#16

Re: Reversible Color Change

05/22/2016 5:30 PM

A sheet of white paper will do it.
Shine a red light on it it looks red... apply white light it looks white... magic.

Del

__________________
health warning: These posts may contain traces of nut.
Register to Reply Off Topic (Score 3)
Guru
Safety - Hazmat - New Member United States - US - Statue of Liberty - New Member Engineering Fields - Chemical Engineering - Old Hand

Join Date: Mar 2011
Location: Lubbock, Texas
Posts: 12922
Good Answers: 147
#18
In reply to #16

Re: Reversible Color Change

05/23/2016 8:25 AM

Looking and being are separate issues. Hence the bathroom debate.

__________________
If it ain't broke, don't fix it. Just build a better one.
Register to Reply
Guru

Join Date: Oct 2006
Location: 44.56024"N 15.307971E
Posts: 3186
Good Answers: 153
#20

Re: Reversible Color Change

05/23/2016 10:53 AM

Allow me to elaborate further:

Imagine an optically clear sphere,or cube,wherein co ordinates have been assigned,on the nano scale.

imagine also 3 (or more) lasers with the ability to illuminate each co ordinate point independently.

These points require the combined energy of at least 3 lasers to change state from one color to another.

Once changed they will remain in this state until 3 more lasers,of a different frequency strike them.

The state of the "dots" could be read by a separate frequency.

This would constitute a very dense 3D memory module.

There may already be such a memory,but I have not heard of it yet.

Which would not surprise me.

I have to exit my cave and send up an antenna by balloon just to connect with civilization.

__________________
"A man never stands so tall as when he stoops to help a child." “I've learned that people will forget what you said, people will forget what you did, but people will never forget how you made them feel.” Maya Angelou.
Register to Reply
Guru
Safety - Hazmat - New Member United States - US - Statue of Liberty - New Member Engineering Fields - Chemical Engineering - Old Hand

Join Date: Mar 2011
Location: Lubbock, Texas
Posts: 12922
Good Answers: 147
#21
In reply to #20

Re: Reversible Color Change

05/23/2016 11:20 AM

Suppose you could now suspend the nano-particles in an optically clear aerogel, and make 3D holographic video to play back on distress call from Princess Leah.

The questions is would this proposed aerogel make the material a off-one record and play?

You will experience long-term data storage if the media is not at least semi-rigid and in a glass state (or single crystalline state). Color centers can be "doped" into crystals with certain techniques (which I am totally inexperienced with).

F type color centers

http://encyclopedia2.thefreedictionary.com/Color+Center

http://www.webexhibits.org/causesofcolor/12.html

http://people.cas.uab.edu/~mirov/Lecture%204-5%20Color%20Center%20Lasers%20Spring%202012.pdf

The above is only a sample of what some have spent careers on in color-center research. There are color center lasers, for example.

__________________
If it ain't broke, don't fix it. Just build a better one.
Register to Reply
Guru

Join Date: Mar 2007
Location: at the beach in Florida
Posts: 18917
Good Answers: 1101
#22
In reply to #20

Re: Reversible Color Change

05/23/2016 10:29 PM

It would be cool if the data could be interpreted into art via laser etching...

Your entire music collection in a 3-D picture of something....

__________________
Life is like riding a bicycle. To keep your balance you must keep moving. A.E.
Register to Reply
Guru

Join Date: Sep 2008
Location: Where the sun sets on OZ
Posts: 1314
Good Answers: 27
#23
In reply to #20

Re: Reversible Color Change

05/24/2016 4:53 AM

OK now it makes sense to me. Maybe others are way ahead of me. You want the colour change to be 'seen' by a device not by eyeballs. In fact it may not need to be a colour change but a density change.

jim

__________________
Where's the KaBoom? There should be a KaBoom!
Register to Reply
Guru
Hobbies - CNC - New Member Hobbies - DIY Welding - New Member Engineering Fields - Electromechanical Engineering - New Member

Join Date: Aug 2007
Posts: 18712
Good Answers: 329
#24

Re: Reversible Color Change

05/24/2016 5:16 AM

A little off topic here maybe. Back in the 80's wasn't there technology that was using biogenetics that would change colors (red/green I recall) with lasers. They were trying to implement this in digital technology as binary communication. Because then computer processing could then be going at the speed of light.

__________________
phoenix911
Register to Reply
Guru
Safety - Hazmat - New Member United States - US - Statue of Liberty - New Member Engineering Fields - Chemical Engineering - Old Hand

Join Date: Mar 2011
Location: Lubbock, Texas
Posts: 12922
Good Answers: 147
#25
In reply to #24

Re: Reversible Color Change

05/24/2016 8:07 AM

I still think color centers present a clear way forward, since these can also be lasers. To read the imprinted data, one would shine a pump wavelength in the z direction, and get laser emission only from the color center zones where the cavity was "tuned" by means of opposing mirrors (one being a partial mirror), along with wavelength specific gain.

Thus light would be sent to the detector only from a narrowly selected zone in the cube.

Various techniques exist to speed up the pulsed light to very fast time scales, as in picoseconds. There is no need for biological chromophores, although they are not excluded from this possibility either.

__________________
If it ain't broke, don't fix it. Just build a better one.
Register to Reply
Guru
Hobbies - CNC - New Member Hobbies - DIY Welding - New Member Engineering Fields - Electromechanical Engineering - New Member

Join Date: Aug 2007
Posts: 18712
Good Answers: 329
#26
In reply to #25

Re: Reversible Color Change

05/24/2016 8:46 AM

the switch (1/0) was actually light sensitive biologics. The speed of the computer would have been based on the speed of the switch and not the speed of the signal.

__________________
phoenix911
Register to Reply
Guru
Safety - Hazmat - New Member United States - US - Statue of Liberty - New Member Engineering Fields - Chemical Engineering - Old Hand

Join Date: Mar 2011
Location: Lubbock, Texas
Posts: 12922
Good Answers: 147
#27
In reply to #26

Re: Reversible Color Change

05/24/2016 8:52 AM

Well, smarty pants, the switch and the signal are pretty closely intertwined at a distance in an optical computer. Consider that a clue.

__________________
If it ain't broke, don't fix it. Just build a better one.
Register to Reply
Guru
Hobbies - CNC - New Member Hobbies - DIY Welding - New Member Engineering Fields - Electromechanical Engineering - New Member

Join Date: Aug 2007
Posts: 18712
Good Answers: 329
#28
In reply to #27

Re: Reversible Color Change

05/24/2016 8:57 AM

with its lasers or biologics, the problem remains the same. it all in the speed of the switch (no matter what that may be) to utilize it.

__________________
phoenix911
Register to Reply
Guru
Safety - Hazmat - New Member United States - US - Statue of Liberty - New Member Engineering Fields - Chemical Engineering - Old Hand

Join Date: Mar 2011
Location: Lubbock, Texas
Posts: 12922
Good Answers: 147
#29
In reply to #28

Re: Reversible Color Change

05/24/2016 11:38 AM

OK. Nobody was arguing that point, most transitions in condensed media are faster than greased lightning anyway.

__________________
If it ain't broke, don't fix it. Just build a better one.
Register to Reply
Register to Reply 29 comments
Interested in this topic? By joining CR4 you can "subscribe" to
this discussion and receive notification when new comments are added.
Copy to Clipboard

Users who posted comments:

Deefburger (1); Del the cat (1); HiTekRedNek (3); horace40 (1); James Stewart (7); jhhassociates (1); JIMRAT (2); JPool (2); lyn (1); phoenix911 (5); PWSlack (1); SolarEagle (3); Usbport (1)

Previous in Forum: Carbon Buildup in Toyota Hybrid EGR Exhaust Baffle   Next in Forum: ASTM G48

Advertisement