You should not redirect "Back", because it would greatly confuse the user. You should not break the most basic user expectations on navigation.
At the same time, you can disable "back" operation, which is the usual technique, there are many articles explaining how to do that. Please see:
http://www.sitekickr.com/blog/back-button-browser-cache[
^].
Alternatively (or additionally), you can handle the event "beforeunload" to notify the user and/or request confirmation:
https://developer.mozilla.org/en-US/docs/Web/Events/beforeunload[
^].
Perhaps if you explain the ultimate purpose, you can get other suggestions on what to do.
—SA