Informing That The Email Is Being Sent?

I've been developing a web application (C#) that has to send an e-mail to around 10 users, how ever, when the user clicks the button is like nothing happened cause the server is processing the e-mails. After the emails have been sent the site is redirected to another page that I have set up, but it takes about 10 seconds until it happens, that way the user will think that the system is frozzen.I'd like to know how do I do to after the user click the Submit button show an advice. I was thinking about put a label, and after the click, the text would change to "Sending the emails", however, I'm making a loop to send the emails, and I believe that if I put the code changing the text before the loop I'll get nothing, once the page will refresh after the loop's execution, am I right