All tire manufacturers use the same competitive absorber, carbon black. This is why tires are black and why tires are not available in designer colors. As carbon black loses the ability to do its job, it turns gray. This is why rubber grays as it ages. Ozone Tire manufacturers use waxes to protect against ozone.
Ozone begins eating away the protective wax and before long reaches the tire polymer.
With UV light and ozone working in concert, degradation starts. The tire dries, checks, and will eventually crack. Other Degradants Petrochemicals and silicone oils can remove the protective waxes and increase the rate of degradation. In the event of warranty sidewall failure, one of the first things tire manufacturers look for is evidence of the use of these types of products. When found, this is often cause for not warranting the sidewall failure.