.popup('open') not working after navigate next page

1) My start up page is 1.aspx and i am using .popup('open') on this page and popup working fine.

2) I navigate to 2.aspx page using $.mobile.changePage( "2.aspx", {transition: "slide"});

3) back to 1.aspx page using $.mobile.changePage( "1.aspx", {transition: "slide"});