If I release some ozone gas (O3) to the atmosphere, for how much time will it stay there in its original form? Does it change to some other form by reacting with other atmospheric constituents?
Really, it is impossible to know how long ozone will persist in the troposphere without knowing what the other chemical concentrations (e.g. CO, NOx, HOx) are and what your photolysis rates are (is it night? cloudy? what latitude? how many hours of sunshine?). Ozone is constantly cycling in the presence of sunlight, so if you are concerned about total overall ozone (not just the molecules you released), you will get a very different answer.
As indicated by DavePhD, the amount of NOx in the region will greatly influence the rate that ozone is converted. In an atmosphere with relatively low levels of NOx, it will persist for a few days. If there is no photolysis (e.g. night time) then ozone won't get re-created and high levels of NOx would titrate out most of your ozone overnight. Though there is a happy medium where moderate levels of NOx will actually increase your total ozone concentrations.
Also it is important to keep in mind that if there is enough CO in the air, OH reactions with ozone will decrease, as the OH will preferably react with CO, and ozone loss will occur more slowly.
Another important thing to consider is that without rain, HNO3 (which is created when NO2 reacts with OH) will not deposit and ozone precursors can persist for many days, allowing more ozone to be re-created. Finally, don't forget that ozone does get dry deposited as well, so the land surface does have some influence on loss rates.
Considering what I've learned about CFC - chlorofluorocarbons, O3 is easily "annihilated" into O2 and chlorine-containing compounds.
See, CFCs are a group of chemicals found in pressurized containers which, as said in its name, contain chlorine, fluorine, or another halogen. When they reach the ozone layer (from anywhere between 1 week and a few years), they form bonds with the ozone and hijack an O atom to form ClO (chlorine monoxide). The by-product O2 sinks downwards for some reason. The ClO meets a free oxygen atom and breaks into more O2, and Cl-.
I would say that ozone would remain in the atmosphere until CFCs come murder it, probably at least 5 weeks.