Because of the hard degradation,the plastic becomes the major pollution. If want the plastic to be natural degradation in the natural world, need around 200~1000 years. But another materials is more tenacious than plastic, and exist longer, it is glass.
Around 4000 years ago, human could make glass. And around 3000 years ago, the ancient Egyptians is proficient in the glass blowing craft. Now many glass products in different periods are found by archeologist, and been preserved well, this showed that hundred years have no effect on glass. If longer, what is the result?
The main ingredient of glass is silica and other oxides, it is non-crystal solid with irregular structure.
Usually, the molecular arrangement of liquid and gas is disorderly, and for solid, it is orderly. glass is solid, but the molecular arrangement is like liquid and gas. Why? In fact, the atomic arrangement of glass is disorderly, but if observe the atom one by one, it is one silicon atom connect with four oxygen atoms. This special arrangement is called “short range order”. This is why glass is tough but fragile.
This special arrangement make glass with super hardness, at the same time, the chemical property of glass is very stable, nearly no chemical reaction between glass and other materials. So it is hard to be corroded for the glass in the natural world.
The big piece glass would break into small pieces under attack, with further attack, the small pieces would be tinier, even smaller than sands. But it is still glass, its glass innate character won’t change.
So glass could exist in the natural world for more than thousands of years.