How Do i make the prefab stop blinking

I am trying to get my prefab to stop blinking after 1.5 seconds. How do I do this. Time is still kind of confusing for me as I am really new to unity. Any help would be greatly appreciated.

using UnityEngine;
using System.Collections;

public class JmpFlasher : MonoBehaviour {

	Material mat;
	public Color color;
	bool isFlashing;
	// Use this for initialization
	void Start () {
		isFlashing = false;
		mat = new Material (Shader.Find("Transparent/Diffuse"));
		mat.color = new Vector4 (color.r,color.g,color.b,1);
		renderer.material = mat;
	// Update is called once per frame
	void Update () {
			mat.color = new Vector4 (color.r,color.g,color.b,(Mathf.Sin (Time.time*8+1)/2));

	public void startFlash (){
		isFlashing = true;

public IEnumerator startFlash (){
isFlashing = true;
yield return new WaitForSeconds(15);
isFlashing = false;

Thanks everyone i’ll give it a try