How to rotate the camera smoothly for just 1 second?

var Destination : Transform;
var rotate : int;
function OnMouseDown () {                        // if i use update it just doesn't stop
   
   Destination.transform.Rotate(0, rotate * Time.deltaTime, 0);   	

}

i need the camera to rotate 90 degrees in one second when i click on the box(link)

thanks for your help
Thomas

Ummm, add a timer ?

OnMouseDown()
{
 active Timer = 60;
}

update()
{
    if( activeTimer > 0 ) 
    {
       activeTimer -= Time.deltaTime;
      //do rotation
    }

}

Thanks you so much