Is this an efficient way of changing a material by script?

I am trying to figure out if there's a more efficient way of changing an object's material by script, in this case when the camera detects if there's an object between the camera and another object. The script I've done so far is:

if(Physics.Raycast(transform.position, -(transform.position-target.transform.position), hit)){

 if(hit.collider.gameObject.name != target.name){
 //hit.collider.gameObject.renderer.enabled =false;
 cont = true;
 gravName = hit.collider.gameObject.name;
 hit.collider.gameObject.Find(hit.collider.gameObject.name).renderer.material = mat2;
    //Debug.Log("Hit"); 
 }
 if(hit.collider.gameObject.name == target.name && cont==true ){
 gameObject.Find(gravName).renderer.material = mat1;
 }

Some pictures:

The script works, but I noticed some lag, so if anyone could point me into the right direction, I would really appreciate it. Thank you.