Optimal Cutting Temperature compound (OCT) is used to embed tissue samples prior to frozen sectioning on a microtome

Microtome

A microtome is a sectioning instrument that allows for the cutting of extremely thin slices of material, known as sections. Microtomes are an important device in microscopy preparation, allowing for the preparation of samples for observation under transmitted light or electron radiation...

-cryostat

Cryostat

A cryostat is a device used to maintain cold cryogenic temperatures. Low temperatures may be maintained within a cryostat by using various refrigeration methods, most commonly using cryogenic fluid bath such as liquid helium. Hence it is usually assembled into a vessel, similar in construction...

. This process is undertaken so as to mount slices (sections) of a sample onto slides for analysis.

Components

Composition/Data on Components:
As stated on the bottle:
"10.24% polyvinyl alcohol
4.26% polyethylene glycol
85.5% non-reactive ingredients"