Unity 3D Javascript appear color fade without coroutine

var colorStart : Color = Color.red;
var colorEnd : Color = Color.green;
var animationDuration : float = 1.0;
private var startTime : float;
private var endTime : float;
private var finished = true;

function Update () {

    if (!finished) {

        var i = Mathf.InverseLerp(startTime, endTime, Time.time);
        renderer.material.color = Color.Lerp (colorStart, colorEnd, i);
        finished = (Time.time > endTime);

    } else {

        if (renderer.enabled) {
            StartAnimation();
        }

    }

}

function StartAnimation() {

    startTime = Time.time;
    endTime = startTime + animationDuration;
    finished = false;

}