The ionization enthalpy refers to the energy required to remove an electron from an atom or ion in its gaseous state. In the case of boron, the first five successive ionization enthalpies are as follows:

1. First ionization enthalpy (800 kJ/mol): This is the energy required to remove the first electron from a neutral boron atom to form a positively charged boron ion (B+). This value is relatively low compared to the subsequent ionization enthalpies.

2. Second ionization enthalpy (2427 kJ/mol): This is the energy required to remove a second electron from the boron ion (B+), resulting in the formation of a doubly charged boron ion (B2+). This value is significantly higher than the first ionization enthalpy because removing an electron from a positively charged ion requires more energy due to the increased attraction between the remaining electrons and the nucleus.

3. Third ionization enthalpy (3658 kJ/mol): This is the energy required to remove a third electron from the doubly charged boron ion (B2+), resulting in the formation of a triply charged boron ion (B3+). Again, this value is higher than the previous ionization enthalpies due to the increased attraction between the remaining electrons and the nucleus.

4. Fourth ionization enthalpy (25024 kJ/mol): This is the energy required to remove a fourth electron from the triply charged boron ion (B3+), resulting in the formation of a quadruply charged boron ion (B4+). This value is significantly higher than the previous ionization enthalpies as removing electrons from highly charged ions requires a large amount of energy.

5. Fifth ionization enthalpy (32824 kJ/mol): This is the energy required to remove a fifth electron from the quadruply charged boron ion (B4+), resulting in the formation of a quintuply charged boron ion (B5+). This value is the highest among the five ionization enthalpies, indicating that removing additional electrons from highly charged ions becomes increasingly difficult.

Overall, the increasing trend in the ionization enthalpies of boron is due to the increasing positive charge on the ion, which leads to stronger electrostatic attraction between the remaining electrons and the nucleus. As a result, more energy is required to remove electrons from highly charged ions.