How to put title of previous and next posts on main page (index.php)?

how do I put title="..." on next_posts_link?

<div class="navigation">
<div class="alignleft"><?php previous_post_link('&laquo; %link') ?></div><br />
<div class="alignright"><?php next_post_link('%link &raquo;') ?></div>
</div>

This is what I use in my single.php, but I don’t know if it also works if the next page has more than one post.