大级别中的会话闪存消息超时

我已经使用控制器在Laravel页面中创建了flash消息。它显示良好,但需要在flash消息中添加超时

if($location_vaidation>0){
     $material_details->location_id=$requested_location;     
     }
     else{
        Session::flash('success', 'please fill the form with valid data');
        return Redirect::to('request');
        exit;           
     }  

查看页面

@if( Session::has("success") )
  <div class="alert alert-success alert-block" role="alert">
  <button class="close" data-dismiss="alert"></button>
  {{ Session::get("success") }}
 </div>
 @endif
 @if( Session::has("error") )
  <div class="alert alert-danger alert-block" role="alert">
  <button class="close" data-dismiss="alert"></button>
  {{ Session::get("error") }}
 </div>
 @endif
 <div class="flash-message"></div>