As michael said.
You may look as well in the following events from session manager.. they are perfect hook for setting the user environment.
cWebSessionManagerStandard [Event OnSessionPropertiesSet] (dataaccess.com)
cWebSessionManagerStandard [Event OnSessionPropertiesClear] (dataaccess.com)
--- By the way ----
What you are seeing is not an effect of browser cache.. but actually your session has just not expired yet. Each session has a default time to live, after x minutes of inactivity.
Check piSessionTimeout of your session manager. Default is 480 minutes.
Regards