Synthese von Spiropyranen

[andrewtretiakov]

Literatur ist eingepflegt, noch ein paar kleinere Anpassungen gemacht. Von meiner Seite her wär's mal fertig...

Excellent! Thank you so much again for sharing! I've been making a few things with your sample so expect a nice surprise soon

[mgritsch]

I've been making a few things with your sample so expect a nice surprise soon

sounds good, very much looking forward to see how you could transfer this into your curriculum and how the feedback was!

Sorry for writing the whole thing in German, but I hope in times of deepl and google translate this isn't too much of an actual barrier.

If you haven't tried yet - I recommend to test them also with direct sunlight (with and without UV filter). Especially the negative photochromism (glad I found some actual literature on that) of the dinitro product works really well that way, much better than with a UV flashlight.

[andrewtretiakov]

sounds good, very much looking forward to see how you could transfer this into your curriculum and how the feedback was!

We had a few trials with different groups of children and some outreach events. The feedback was overwhelmingly excellent! They enjoyed very much testing the pre-prepared laminated sheets with the photochromic dye with different sources of light. Using various monochromatic laser pointers, coloured LEDs, UV torches and the sun. Then they compared how long it took for the colour to reverse to transparent by placing them in the dark or illuminating with other sources of light such as a strong white light and attempted to distinguish between photochemical and thermal reaction pathways. We also checked for fluorescence, solvatochromism in different solvents and even in different polymer matrices by embedding the dye in them. Others, used different filters (coloured filters, sunglasses, sunscreens, translucent materials etc.) to try and see how effective they blocked UV from the sun by not observing a colour change in the laminated photochromic dye sheet or colourless solution. At school, most students study photochemical free radical reactions like hydrogen and chlorine mixtures exploding in a test tube (blowing the bung off) when UV light is shone on it or using a flash from a camera or even by igniting a piece of magnesium ribbon but that's about it. This gave them a completely new way of looking at photochemical reactions, looking at isomerizations induced by light, changes in structure, uses and applications in sunscreens, photochemical synthesis, etc.

These are just a glimpse of the things we started doing. There is nothing definite yet but we are trying to include it in the scheme of work and as I said before outreach and public events.

More on that and a small thank you surprise in your notifications.

Sorry for writing the whole thing in German, but I hope in times of deepl and google translate this isn't too much of an actual barrier.

If you haven't tried yet - I recommend to test them also with direct sunlight (with and without UV filter). Especially the negative photochromism (glad I found some actual literature on that) of the dinitro product works really well that way, much better than with a UV flashlight.

No worries, I use google translate or deepl whenever I access this wonderful website. I should really learn German.

I have not tried the negative photochromism yet but is next in my to do list. Hopefully, when summer comes along and the sun is shining... for now it's still bloody freezing here.

[mgritsch]

Great to hear it was a success and fun for everyone and worked well, you don’t happen to have any photos of such an event to share here?

[andrewtretiakov]

Great to hear it was a success and fun for everyone and worked well, you don’t happen to have any photos of such an event to share here?

Thank you! But with all the excitement I forgot to take photos (can you believe that?) ... Plus nowadays we need written permission from parents/guardians to take photos of their children so it would have made it difficult. Next time, next event I will post some photos where you cannot see their faces so it should be alright.

Photochromic LEGO figures:
https://www.youtube.com/shorts/_Rkayzr0 ... ture=share

Cheers,
Andres