Light is vibrating in all directions. However, special films polarize light by allowing only light that is vibrating in one direction to pass through them. The above films are both 90 degree polarizing films and so they both allow light vibrating from side to side to pass through.
On the left, the films are aligned with one another as both have their eyes on top. The light passing through both films is no different from the light passing through them separately. On the right one, the film is rotated so that the eye is to the side. This changes the orientation of the rotated film so that it blocks light vibrating from side to side while allowing light vibrating up and down to pass through. That means that the light passing through the first film is blocked by the rotated film. That is why the area where the films overlap is totally dark, This dark space is where the two films are "crossed polarized" with one another. See the video demo below.
The glasses will only be crossed polarized with zero degree portal rings if the eye on the ring is rotated to the side.
The glasses in your Glitterins® Science kits have zero degree polarizing films in them and this is true for most polarizing glasses designed to block glare that happens when sunlight is reflected off streets and the surface of water.
Glare is actually light polarized by bouncing off a smooth surface such that it is mostly vibrating from side to side. As the glasses only allow light that is vibrating up and down to pass, it blocks the glare (light vibrating from side to side).
Fishermen use polarizing glasses to block glare in the surface of water to see the fish below. The glasses in your Glitterins® Science kits are crossed polarized with the films in your regular Glitterins® Magic Green Portal rings when the eye is on top unless the rings are marked as Zero Degree Portal Rings on the back, in which case the eye on the ring needs to be rotated to the side to be crossed polarized with the glasses.
Some Glitterins® Science kits have zero degree portal rings that are marked on the back. These will be crossed polarized with the regular 90 degree portal rings when both have their eyes on top.