Why don't aircraft (commercial and military) use reflective visor windshields? Just like those used on an astronaut's helmet, these reflective visors can help in better visibility when facing the sun (or any bright light source). But the windshields of most aircraft (commercial and military) look transparent from both sides. The whole point behind the question is to find out if it was experimented and if yes, why was it dropped?
Reflective materials cut down the amount of light let into the cockpit, which is useful in very bright sunlight, but would be undesirable at night. At night these materials could potentially blind the pilot, so you would have to make these materials retractable somehow, which would add complexity and weight. Over time these coating would be damaged by airborne debris, smashed bugs, and regular wear and tear. Add this that these coatings are expensive - outfitting them would be a significant cost. 

Add to this that ever pilot would have different tinting needs - some people with less sensitive eyesight would need less tinting and others more. It's far cheaper and more effective for people to simply buy sunglasses.