[NowThenGoodBad]

You are correct.

Materials scientist and polymer scientists here:

Just because it depolymerizes doesn't mean it does so into happy stuff. Photodegradation is the process of degrading with the application of photons (typically in the visible to UV range). Many things, especially plastic things, degrade in the sunlight, some faster than others. But then, when it degrades, when those monomers (single repeat used to make a polymer) split up, what did you just release into the environment?

If you want to understand this process more, here's a good and accessible read: [Photodegradation and photostabilization of polymers, especially polystyrene: review](https://www.ncbi.nlm.nih.gov/pmc/articles/PMC4320144/)

[inflatableDodo]

Aww, my first thought was food packaging that auto-sublimates after opening.