I have two ways in mind:
1. One way of doing that would be in Page 1, add a jQuery that will call the server at certain intervals and check for changes. If there are changes in the server then obtain the new data and display in the page.
2. Use unload or unbeforeunload events that will help you run a script when Page 2 is closed and then look at window.opener.reload() function.
It depends on how you are opening Page2 from Page1.
Case-1: Opening Page2 using "iframes" and Dialog | jQuery UI to open other pages as model regions. In this case, you can easily trigger any JS function of Parent page (Page1) from Model page (Page2).