Flash point is the lowest temperature at which a substance can catch fire if ignited.
I hope you don’t heat your formulation over a Bunsen burner

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What plays a role is the boiling point (which is usually well above 70°C. However, in case of fragrances and essential oils, vapour pressure usually dominates and this is less dependent on temperature given that room temp remains the same during production. Hence, time is what may matter most.
Without knowing the chemical structures/names of your fragrances and the overall composition of your formulation makes it impossible to predict chemical stability.
Another probably more likely possibility may be that there is no degradation but you might encounter a ‘solubility issue’. Meaning, the base imparts fixation of certain molecules which changes volatilisation and subsequently fragrance perception/scent. Firmenich (a renowned company producing fragrances and white label perfumes) published some articles showing that the most volatile molecules aren’t necessarily the ones which actually volatilise first and hence, the flavour cascade from top over middle to base notes may not be what you expect or would smell when mixing pure fragrances compared to dissolved/fixed ones.
PS Please use °C. Only some backwood countries have difficulties
with the rational, reliable, easy to use, scientific, linear metric system and still adhere certainly for no more than sentimental reasons to imperial (is that word even allowed to be used in light of #BLM?) units :blush: .