You have the right idea there.
You could create a Recordset1 on your userProfile.php that checks for logins that have the requirePW=Y. If it finds that to be true redirect to change the PW. Below is a quick solution to assist in accomplishing this.
<?php
if ($row_Recordset1['requirePW'] == 'Y') {
?>
<form>
<INPUT TYPE="BUTTON" VALUE="Please Change Your Password" ONCLICK="window.location.href='force_chg_pwd.php'">
</form>
<?php
} else {
}
?>