First, I would like to state that I am not well educated in chemistry, so please forgive any mistakes on my part.

 

I have a spray botte with half water and half bleach inside, and it sits near a window that has the blinds down, but it still let's sunlight through. I was looking at the bottle this evening when I found a cluster of hard white "stuff" on the side and a ring of comparable white stuff atop the plastic sheet it sits on. I scratched it away and it came off very easily. The cluster was as wide as a penny and the height of a penny and a half. Any ideas of what it could be? It smells like bleach and whatever happened left an embroidered patch sitting next to the bottle with a white spot and a few parted stitches. I am thinking it is the result of evaporation, what might you think?

It's probably a mixture of solids, salt, sodium chlorate, sodium hypochlorite (bleach). Most likely due to evaporation and decomposition. You can read more here:

http://en.wikipedia.org/wiki/Sodium_hypochlorite

Thanks!

likely to be a lot more NaCl than NaClO.

NaClO In't very stable.

There may be some NaClO3 as well (and other stuff too).