As far as I know, what you're referring to is caused aerating the wine, i.e., letting it breathe. Opening it up exposes it to oxygen, which is good and bad depending upon where you are in the lifecycle of wine and how much it gets. In the case of most newly opened wine, reds in particular, the wine greatly benefits from about 30 minutes to an hour of air time. This let's some of the sulfur in the wine realign itself or drift off, and many of the other good things in wine to relax (like tannins) and others to open up.
The analogy of a flower bud is often used. Opening a bottle of wine is like the bud, but to truly appreciate it you need to let it breathe and open up.
I'll leave it to a scientist or scholar to better explain how phenols work and all those other strange names that I just refer to as good smells.
In order to get your first day wine tasting like your second day wine I recommend decanting it and letting it sit for an hour or pouring it through one of those vortex type gizmos that are out there to quickly add oxygen to wine as you pour it.
I look forward to other answers, perhaps better answers.