wp post title in foundation tooltip

I would like to show the next/prev post link title in a tooltip, i tried several options, but it won't display it. The place is "SHOW POST TITLE HERE". the code:

<?php next_post_link('%link', '<span data-tooltip aria-haspopup="true" class="has-tip tip-bottom" title="SHOW POST TITLE HERE"><i class="fa fa-angle-left fa-2x"></i></span>
'); ?>

thnx in advance

via Chebli Mohamed