You can add some meta tags to your header to prevent caching, though I'm not sure how reliable they are.
Alternatively, I gather it works better to add this to a .htaccess file (if your site is served by Apache, of course):
<meta Http-Equiv="Cache-Control" Content="no-cache">
<meta Http-Equiv="Pragma" Content="no-cache">
<meta Http-Equiv="Expires" Content="0">
I've never tried any of these options, though, so this is just hearsay.
Header set Cache-Control "max-age=0, no-cache, no-store, private"
Header set Pragma "no-cache"
Header set Expires "0"