Raman Spectroscopy

prune

Does anyone know what the cause of dissapearance of peaks in a Raman spectrum could mean?

I have an amorphous polycarbonate material and I have treated this with a low intensity UV laser. In the untreated sample the spectrum has a few extra peaks (that I can't identify) than in the spectrum of the treated sample. What would cause these peaks to dissapear?

Any help would be great!:D

Phototoxin

contamination of samples could cause it but probably the uv laser has caused some of the material to degrade or react. UV can do that ya know!

Professor_Fink

Phototoxin wrote: »

contamination of samples could cause it but probably the uv laser has caused some of the material to degrade or react. UV can do that ya know!

Yes, I was thinking the same thing, although spectroscopy isn't really my thing. Could also be a phase transition.

Is the material solid or in solution?

prune

It's a soild polymer foil. I am pretty sure the UV is reacting with the polymer. It's kind of the point of the irradiation, I just dont know what kinda of interaction would cause the complete dissapearance of these peaks. I had thought of a phase transtition, and it does seem to me to be the most likely explanation but I'm just not sure about what kinda of a phase transition. I also was just wondering if there were any other (obvious) reasons I may have overlooked.

SOL

Do you have the chemical structure of the polymer? Do you reckon you are losing a particular functional group to a photoreaction?

Does this loss of peaks happen gradually and proportionately to the ammount of UV light used? Does it affect all of the material or just the exposed surface?