|MadSci Network: Chemistry|
I can't find the solubility information you need on-line but I'll describe the behavior to you. You can verify my explanation using a carbon dioxide solubility table from "Perry's Chemical Engineers' Handbook" if you'd like (I'd give you a page number but I have a very old copy...).
Yes, temperature does affect how long your soda stays carbonated after it has been opened because temperature affects the solubility of carbon dioxide in the beverage. The colder the liquid, the more soluble the CO2 is and the longer it will stay in solution (which is why it doesn't go flat as fast if you stick it back in the fridge). If you look at Perry's, the solubility at atmospheric pressure is maximized at freezing (0 degrees C), so the colder your fridge, the better.
To keep the soda carbonated for as long as possible, make sure it is as cold as you can make it BEFORE you open the container. Not only will you minimize the CO2 lost when you open it, but it won't foam as much. Replace the cap as soon as possible (you are on your own if you are drinking out of a can), and put it back in the fridge when you are done with it. I don't really have any other suggestions... except that glass bottles retain CO2 better than plastic (though there aren't a whole lot of those around anymore). It has to do with the gas permeability of the packaging material itself.
I hope this information helps. Sodas are much more complicated than they look!
Try the links in the MadSci Library for more information on Chemistry.