Will paper heated in outer space just evaporate? If a piece of paper is heated in outer space (or in a vacuum chamber), what will I see? Will it just evaporate? I can't imagine that it first melts...
 A: As @Vercassivelaunos notes, the paper pyrolyzes or thermally decomposes. As the heating process begins, all condensed matter is sublimating very slowly into the vacuum according to its corresponding vapor pressure. Any volatile adsorbed substances, such as water, evaporates quickly (by definition of volatile), termed outgassing.
The stability of phases and compounds is defined by the Gibbs free energy. Broadly, Nature prefers both strong bonding (low enthalpy) and many possibilities (high entropy). The Gibbs free energy represents both, and the temperature coefficient of the entropy term means that the higher-entropy phase or product is always favored at higher temperature. Consequently, the cellulose in the paper, which was stable at room temperature, decomposes at high temperature into smaller units, including gases, because of the higher entropy of the gas phase. H2, CO2,
CO, CH4, C2H6, C2H4, and larger gaseous organics disperse into the void. The remaining elemental solid ash ultimately sublimates with exponentially increasing speed upon continued heating.
A: Charcoal is the product of heating wood in the absence of oxygen. I would expect paper to become a sheet of charcoal. This is mostly carbon, not ash.
Of course, at high temperature the carbon will evaporate, leaving ash, and at higher temperature that will also.
